CVE-2025-21796: nfsd: clear acl_access/acl_default after releasing them

Published Feb 27, 2025
·
Updated

In the Linux kernel, the following vulnerability has been resolved:

nfsd: clear aclaccess/acldefault after releasing them

If getting acldefault fails, aclaccess and acldefault will be released simultaneously. However, aclaccess will still retain a pointer pointing to the released posixacl, which will trigger a WARNING in nfs3svcreleasegetacl like this:

------------[ cut here ]------------ refcountt: underflow; use-after-free. WARNING: CPU: 26 PID: 3199 at lib/refcount.c:28 refcountwarnsaturate+0xb5/0x170 Modules linked in: CPU: 26 UID: 0 PID: 3199 Comm: nfsd Not tainted 6.12.0-rc6-00079-g04ae226af01f-dirty #8 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 RIP: 0010:refcountwarnsaturate+0xb5/0x170 Code: cc cc 0f b6 1d b3 20 a5 03 80 fb 01 0f 87 65 48 d8 00 83 e3 01 75 e4 48 c7 c7 c0 3b 9b 85 c6 05 97 20 a5 03 01 e8 fb 3e 30 ff <0f> 0b eb cd 0f b6 1d 8a3 RSP: 0018:ffffc90008637cd8 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff83904fde RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffff88871ed36380 RBP: ffff888158beeb40 R08: 0000000000000001 R09: fffff520010c6f56 R10: ffffc90008637ab7 R11: 0000000000000001 R12: 0000000000000001 R13: ffff888140e77400 R14: ffff888140e77408 R15: ffffffff858b42c0 FS: 0000000000000000(0000) GS:ffff88871ed00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000562384d32158 CR3: 000000055cc6a000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ? refcountwarnsaturate+0xb5/0x170 ? warn+0xa5/0x140 ? refcountwarnsaturate+0xb5/0x170 ? reportbug+0x1b1/0x1e0 ? handlebug+0x53/0xa0 ? excinvalidop+0x17/0x40 ? asmexcinvalidop+0x1a/0x20 ? ticknohztickstopped+0x1e/0x40 ? refcountwarnsaturate+0xb5/0x170 ? refcountwarnsaturate+0xb5/0x170 nfs3svcreleasegetacl+0xc9/0xe0 svcprocesscommon+0x5db/0xb60 ? pfxsvcprocesscommon+0x10/0x10 ? rcureadunlock+0x69/0xa0 ? pfxnfsddispatch+0x10/0x10 ? svcxprtreceived+0xa1/0x120 ? xdrinitdecode+0x11d/0x190 svcprocess+0x2a7/0x330 svchandlexprt+0x69d/0x940 svcrecv+0x180/0x2d0 nfsd+0x168/0x200 ? pfxnfsd+0x10/0x10 kthread+0x1a2/0x1e0 ? kthread+0xf4/0x1e0 ? pfxkthread+0x10/0x10 retfromfork+0x34/0x60 ? pfxkthread+0x10/0x10 retfromforkasm+0x1a/0x30 </TASK> Kernel panic - not syncing: kernel: paniconwarn set ...

Clear aclaccess/acldefault after posixaclrelease is called to prevent UAF from being triggered.

Other sources

In the Linux kernel, the following vulnerability has been resolved:

nfsd: clear aclaccess/acldefault after releasing them

If getting acldefault fails, aclaccess and acldefault will be released simultaneously. However, aclaccess will still retain a pointer pointing to the released posixacl, which will trigger a WARNING in nfs3svcreleasegetacl like this:

------------[ cut here ]------------ refcountt: underflow; use-after-free. WARNING: CPU: 26 PID: 3199 at lib/refcount.c:28 refcountwarnsaturate+0xb5/0x170 Modules linked in: CPU: 26 UID: 0 PID: 3199 Comm: nfsd Not tainted 6.12.0-rc6-00079-g04ae226af01f-dirty #8 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 RIP: 0010:refcountwarnsaturate+0xb5/0x170 Code: cc cc 0f b6 1d b3 20 a5 03 80 fb 01 0f 87 65 48 d8 00 83 e3 01 75 e4 48 c7 c7 c0 3b 9b 85 c6 05 97 20 a5 03 01 e8 fb 3e 30 ff 0f 0b eb cd 0f b6 1d 8a3 RSP: 0018:ffffc90008637cd8 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff83904fde RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffff88871ed36380 RBP: ffff888158beeb40 R08: 0000000000000001 R09: fffff520010c6f56 R10: ffffc90008637ab7 R11: 0000000000000001 R12: 0000000000000001 R13: ffff888140e77400 R14: ffff888140e77408 R15: ffffffff858b42c0 FS: 0000000000000000(0000) GS:ffff88871ed00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000562384d32158 CR3: 000000055cc6a000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: TASK ? refcountwarnsaturate+0xb5/0x170 ? warn+0xa5/0x140 ? refcountwarnsaturate+0xb5/0x170 ? reportbug+0x1b1/0x1e0 ? handlebug+0x53/0xa0 ? excinvalidop+0x17/0x40 ? asmexcinvalidop+0x1a/0x20 ? ticknohztickstopped+0x1e/0x40 ? refcountwarnsaturate+0xb5/0x170 ? refcountwarnsaturate+0xb5/0x170 nfs3svcreleasegetacl+0xc9/0xe0 svcprocesscommon+0x5db/0xb60 ? pfxsvcprocesscommon+0x10/0x10 ? rcureadunlock+0x69/0xa0 ? pfxnfsddispatch+0x10/0x10 ? svcxprtreceived+0xa1/0x120 ? xdrinitdecode+0x11d/0x190 svcprocess+0x2a7/0x330 svchandlexprt+0x69d/0x940 svcrecv+0x180/0x2d0 nfsd+0x168/0x200 ? pfxnfsd+0x10/0x10 kthread+0x1a2/0x1e0 ? kthread+0xf4/0x1e0 ? pfxkthread+0x10/0x10 retfromfork+0x34/0x60 ? pfxkthread+0x10/0x10 retfromforkasm+0x1a/0x30 /TASK Kernel panic - not syncing: kernel: paniconwarn set ...

Clear aclaccess/acldefault after posixaclrelease is called to prevent UAF from being triggered.

— IBM

Affected Software

225 affected componentsFixes available
Linux Foundation Linux Kernel
IBM Verify Identity Access<=11.0 - 11.0.2
IBM Security Verify Access<=10.0 - 10.0.9.1
IBM Verify Identity Access Container<=11.0 - 11.0.2
IBM Security Verify Access Container<=10.0 - 10.0.9.1
Microsoft azl3 kernel 6.6.78.1-3<6.6.82.1-1
6.6.82.1-1
Microsoft cbl2 kernel 5.15.176.3-3<5.15.180.1-1
5.15.180.1-1
Microsoft azl3 kernel 6.6.82.1-1<6.6.82.1-1
6.6.82.1-1
Microsoft cbl2 kernel 5.15.180.1-1<5.15.180.1-1
5.15.180.1-1
Linux Linux kernel>=2.6.13<5.10.235
Linux Linux kernel>=5.11<5.15.179
Linux Linux kernel>=5.16<6.1.129
Linux Linux kernel>=6.2<6.6.79
Linux Linux kernel>=6.7<6.12.16
Linux Linux kernel>=6.13<6.13.4
Linux Linux kernel=6.14-rc1
Linux Linux kernel=6.14-rc2
ubuntu/linux*
ubuntu/linux-aws<4.4.0-1148.154
4.4.0-1148.154
ubuntu/linux-azure<4.15.0-1193.208~14.04.1
4.15.0-1193.208~14.04.1
ubuntu/linux-lts-xenial<4.4.0-273.307~14.04.1
4.4.0-273.307~14.04.1
ubuntu/linux<4.4.0-273.307
4.4.0-273.307
ubuntu/linux-aws<4.4.0-1186.201
4.4.0-1186.201
ubuntu/linux-aws-hwe<4.15.0-1185.198~16.04.1
4.15.0-1185.198~16.04.1
ubuntu/linux-azure<4.15.0-1193.208~16.04.1
4.15.0-1193.208~16.04.1
ubuntu/linux-gcp<4.15.0-1178.195~16.04.1
4.15.0-1178.195~16.04.1
ubuntu/linux-hwe<4.15.0-242.254~16.04.1
4.15.0-242.254~16.04.1
ubuntu/linux-kvm<4.4.0-1149.160
4.4.0-1149.160
ubuntu/linux-oracle<4.15.0-1148.159~16.04.1
4.15.0-1148.159~16.04.1
ubuntu/linux-hwe-edge*
ubuntu/linux-fips<4.4.0-1119.126
4.4.0-1119.126
ubuntu/linux-fips*
ubuntu/linux<4.15.0-242.254
4.15.0-242.254
ubuntu/linux-aws<4.15.0-1185.198
4.15.0-1185.198
ubuntu/linux-aws-5.0*
ubuntu/linux-aws-5.3*
ubuntu/linux-aws-5.4<5.4.0-1151.161~18.04.1
5.4.0-1151.161~18.04.1
ubuntu/linux-azure*
ubuntu/linux-azure-4.15<4.15.0-1193.208
4.15.0-1193.208
ubuntu/linux-azure-5.3*
ubuntu/linux-azure-5.4<5.4.0-1154.161~18.04.1
5.4.0-1154.161~18.04.1
ubuntu/linux-azure-edge*
ubuntu/linux-gcp*
ubuntu/linux-gcp-4.15<4.15.0-1178.195
4.15.0-1178.195
ubuntu/linux-gcp-5.3*
ubuntu/linux-gcp-5.4<5.4.0-1154.163~18.04.1
5.4.0-1154.163~18.04.1
ubuntu/linux-gke-4.15*
ubuntu/linux-gke-5.4*
ubuntu/linux-gkeop-5.4*
ubuntu/linux-hwe*
ubuntu/linux-hwe-5.4<5.4.0-222.242~18.04.1
5.4.0-222.242~18.04.1
ubuntu/linux-hwe-edge*
ubuntu/linux-ibm-5.4<5.4.0-1097.102~18.04.1
5.4.0-1097.102~18.04.1
ubuntu/linux-kvm<4.15.0-1168.173
4.15.0-1168.173
ubuntu/linux-oem*
ubuntu/linux-oracle<4.15.0-1147.158
4.15.0-1147.158
ubuntu/linux-oracle-5.0*
ubuntu/linux-oracle-5.3*
ubuntu/linux-oracle-5.4<5.4.0-1149.159~18.04.1
5.4.0-1149.159~18.04.1
ubuntu/linux-raspi-5.4<5.4.0-1134.147~18.04.1
5.4.0-1134.147~18.04.1
ubuntu/linux-aws-fips<4.15.0-2123.129
4.15.0-2123.129
ubuntu/linux-azure-fips<4.15.0-2102.108
4.15.0-2102.108
ubuntu/linux-fips<4.15.0-1140.151
4.15.0-1140.151
ubuntu/linux-gcp-fips<4.15.0-2086.92
4.15.0-2086.92
ubuntu/linux-aws-fips*
ubuntu/linux-azure-fips*
ubuntu/linux-fips*
ubuntu/linux-gcp-fips*
ubuntu/linux-aws-5.15<5.15.0-1084.91~20.04.1
5.15.0-1084.91~20.04.1
ubuntu/linux-azure-5.15<5.15.0-1089.98~20.04.1
5.15.0-1089.98~20.04.1
ubuntu/linux-gcp-5.15<5.15.0-1083.92~20.04.1
5.15.0-1083.92~20.04.1
ubuntu/linux-ibm-5.15<5.15.0-1076.79~20.04.1
5.15.0-1076.79~20.04.1
ubuntu/linux-intel-iotg-5.15<5.15.0-1079.85~20.04.1
5.15.0-1079.85~20.04.1
ubuntu/linux-lowlatency-hwe-5.15<5.15.0-140.150~20.04.1
5.15.0-140.150~20.04.1
ubuntu/linux-oracle-5.15<5.15.0-1081.87~20.04.1
5.15.0-1081.87~20.04.1
ubuntu/linux-riscv-5.15<5.15.0-1079.83~20.04.1
5.15.0-1079.83~20.04.1
ubuntu/linux<5.4.0-222.242
5.4.0-222.242
ubuntu/linux-aws<5.4.0-1151.161
5.4.0-1151.161
ubuntu/linux-aws-5.11*
ubuntu/linux-aws-5.13*
ubuntu/linux-aws-5.8*
ubuntu/linux-azure<5.4.0-1154.161
5.4.0-1154.161
ubuntu/linux-azure-5.11*
ubuntu/linux-azure-5.13*
ubuntu/linux-azure-5.8*
ubuntu/linux-azure-fde*
ubuntu/linux-bluefield<5.4.0-1110.117
5.4.0-1110.117
ubuntu/linux-gcp<5.4.0-1154.163
5.4.0-1154.163
ubuntu/linux-gcp-5.11*
ubuntu/linux-gcp-5.13*
ubuntu/linux-gcp-5.8*
ubuntu/linux-gke*
ubuntu/linux-gke-5.15*
ubuntu/linux-gkeop*
ubuntu/linux-gkeop-5.15*
ubuntu/linux-hwe-5.11*
ubuntu/linux-hwe-5.13*
ubuntu/linux-hwe-5.15<5.15.0-142.152~20.04.1
5.15.0-142.152~20.04.1
ubuntu/linux-hwe-5.8*
ubuntu/linux-ibm<5.4.0-1097.102
5.4.0-1097.102
ubuntu/linux-intel-5.13*
ubuntu/linux-iot<5.4.0-1055.58
5.4.0-1055.58
ubuntu/linux-kvm<5.4.0-1138.147
5.4.0-1138.147
ubuntu/linux-nvidia-tegra-5.15<5.15.0-1039.39~20.04.1
5.15.0-1039.39~20.04.1
ubuntu/linux-oem-5.10*
ubuntu/linux-oem-5.13*
ubuntu/linux-oem-5.6*
ubuntu/linux-oracle<5.4.0-1149.159
5.4.0-1149.159
ubuntu/linux-oracle-5.11*
ubuntu/linux-oracle-5.13*
ubuntu/linux-oracle-5.8*
ubuntu/linux-raspi<5.4.0-1134.147
5.4.0-1134.147
ubuntu/linux-raspi2*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.11*
ubuntu/linux-riscv-5.8*
ubuntu/linux-xilinx-zynqmp<5.4.0-1069.73
5.4.0-1069.73
ubuntu/linux-aws-fips<5.4.0-1151.161+fips1
5.4.0-1151.161+fips1
ubuntu/linux-azure-fips<5.4.0-1155.162+fips1
5.4.0-1155.162+fips1
ubuntu/linux-fips<5.4.0-1125.135
5.4.0-1125.135
ubuntu/linux-gcp-fips<5.4.0-1154.163+fips1
5.4.0-1154.163+fips1
ubuntu/linux-aws-fips*
ubuntu/linux-azure-fips*
ubuntu/linux-fips*
ubuntu/linux-gcp-fips*
ubuntu/linux<5.15.0-140.150
5.15.0-140.150
ubuntu/linux-allwinner-5.19*
ubuntu/linux-aws<5.15.0-1084.91
5.15.0-1084.91
ubuntu/linux-aws-5.19*
ubuntu/linux-aws-6.2*
ubuntu/linux-aws-6.5*
ubuntu/linux-aws-6.8<6.8.0-1035.37~22.04.1
6.8.0-1035.37~22.04.1
ubuntu/linux-azure<5.15.0-1089.98
5.15.0-1089.98
ubuntu/linux-azure-5.19*
ubuntu/linux-azure-6.2*
ubuntu/linux-azure-6.5*
ubuntu/linux-azure-6.8<6.8.0-1034.39~22.04.1
6.8.0-1034.39~22.04.1
ubuntu/linux-azure-fde<5.15.0-1089.98.1
5.15.0-1089.98.1
ubuntu/linux-azure-fde-5.19*
ubuntu/linux-azure-fde-6.2*
ubuntu/linux-gcp<5.15.0-1083.92
5.15.0-1083.92
ubuntu/linux-gcp-5.19*
ubuntu/linux-gcp-6.2*
ubuntu/linux-gcp-6.5*
ubuntu/linux-gcp-6.8<6.8.0-1036.38~22.04.1
6.8.0-1036.38~22.04.1
ubuntu/linux-gke<5.15.0-1081.87
5.15.0-1081.87
ubuntu/linux-gkeop<5.15.0-1066.74
5.15.0-1066.74
ubuntu/linux-hwe-5.19*
ubuntu/linux-hwe-6.2*
ubuntu/linux-hwe-6.5*
ubuntu/linux-hwe-6.8<6.8.0-78.78~22.04.1
6.8.0-78.78~22.04.1
ubuntu/linux-ibm<5.15.0-1076.79
5.15.0-1076.79
ubuntu/linux-ibm-6.8<6.8.0-1033.33~22.04.1
6.8.0-1033.33~22.04.1
ubuntu/linux-intel-iot-realtime*
ubuntu/linux-intel-iotg<5.15.0-1079.85
5.15.0-1079.85
ubuntu/linux-kvm<5.15.0-1080.85
5.15.0-1080.85
ubuntu/linux-lowlatency<5.15.0-140.150
5.15.0-140.150
ubuntu/linux-lowlatency-hwe-5.19*
ubuntu/linux-lowlatency-hwe-6.2*
ubuntu/linux-lowlatency-hwe-6.5*
ubuntu/linux-lowlatency-hwe-6.8<6.8.0-78.78.1~22.04.1
6.8.0-78.78.1~22.04.1
ubuntu/linux-nvidia<5.15.0-1078.79
5.15.0-1078.79
ubuntu/linux-nvidia-6.2*
ubuntu/linux-nvidia-6.5*
ubuntu/linux-nvidia-6.8<6.8.0-1035.38~22.04.1
6.8.0-1035.38~22.04.1
ubuntu/linux-nvidia-tegra<5.15.0-1037.37
5.15.0-1037.37
ubuntu/linux-nvidia-tegra-igx<5.15.0-1026.26
5.15.0-1026.26
ubuntu/linux-oem-5.17*
ubuntu/linux-oem-6.0*
ubuntu/linux-oem-6.1*
ubuntu/linux-oem-6.5*
ubuntu/linux-oracle<5.15.0-1081.87
5.15.0-1081.87
ubuntu/linux-oracle-6.5*
ubuntu/linux-oracle-6.8<6.8.0-1032.33~22.04.1
6.8.0-1032.33~22.04.1
ubuntu/linux-raspi<5.15.0-1078.81
5.15.0-1078.81
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.19*
ubuntu/linux-riscv-6.5*
ubuntu/linux-riscv-6.8<6.8.0-78.78~22.04.1
6.8.0-78.78~22.04.1
ubuntu/linux-starfive-5.19*
ubuntu/linux-starfive-6.2*
ubuntu/linux-starfive-6.5*
ubuntu/linux-xilinx-zynqmp<5.15.0-1050.54
5.15.0-1050.54
ubuntu/linux-bluefield<5.15.0-1066.68
5.15.0-1066.68
ubuntu/linux-intel-iot-realtime<5.15.0-1077.79
5.15.0-1077.79
ubuntu/linux-realtime<5.15.0-1084.93
5.15.0-1084.93
ubuntu/linux-realtime-6.8<6.8.1-1030.31~22.04.1
6.8.1-1030.31~22.04.1
ubuntu/linux-aws-fips*
ubuntu/linux-azure-fips*
ubuntu/linux-fips*
ubuntu/linux-gcp-fips*
ubuntu/linux-aws-fips<5.15.0-1084.91+fips1
5.15.0-1084.91+fips1
ubuntu/linux-azure-fips<5.15.0-1089.98+fips1
5.15.0-1089.98+fips1
ubuntu/linux-fips<5.15.0-140.150+fips1
5.15.0-140.150+fips1
ubuntu/linux-gcp-fips<5.15.0-1083.92+fips1
5.15.0-1083.92+fips1
ubuntu/linux<6.8.0-78.78
6.8.0-78.78
ubuntu/linux-aws<6.8.0-1035.37
6.8.0-1035.37
ubuntu/linux-azure<6.8.0-1034.39
6.8.0-1034.39
ubuntu/linux-azure-6.11<6.11.0-1015.15~24.04.1
6.11.0-1015.15~24.04.1
ubuntu/linux-azure-nvidia<6.8.0-1022.23
6.8.0-1022.23
ubuntu/linux-gcp<6.8.0-1036.38
6.8.0-1036.38
ubuntu/linux-gcp-6.11<6.11.0-1015.15~24.04.1
6.11.0-1015.15~24.04.1
ubuntu/linux-gke<6.8.0-1032.36
6.8.0-1032.36
ubuntu/linux-gkeop<6.8.0-1019.21
6.8.0-1019.21
ubuntu/linux-hwe-6.11<6.11.0-26.26~24.04.1
6.11.0-26.26~24.04.1
ubuntu/linux-ibm<6.8.0-1033.33
6.8.0-1033.33
ubuntu/linux-intel*
ubuntu/linux-lowlatency<6.8.0-78.78.1
6.8.0-78.78.1
ubuntu/linux-lowlatency-hwe-6.11<6.11.0-1014.15~24.04.1
6.11.0-1014.15~24.04.1
ubuntu/linux-nvidia<6.8.0-1035.38
6.8.0-1035.38
ubuntu/linux-nvidia-6.11<6.11.0-1010.10
6.11.0-1010.10
ubuntu/linux-nvidia-lowlatency<6.8.0-1035.38.1
6.8.0-1035.38.1
ubuntu/linux-nvidia-tegra<6.8.0-1009.9
6.8.0-1009.9
ubuntu/linux-oem-6.11<6.11.0-1022.22
6.11.0-1022.22
ubuntu/linux-oem-6.8*
ubuntu/linux-oracle<6.8.0-1032.33
6.8.0-1032.33
ubuntu/linux-raspi<6.8.0-1035.39
6.8.0-1035.39
ubuntu/linux-raspi-realtime*
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-xilinx<6.8.0-1017.18
6.8.0-1017.18
ubuntu/linux-raspi-realtime<6.8.0-2028.29
6.8.0-2028.29
ubuntu/linux-realtime<6.8.1-1030.31
6.8.1-1030.31
ubuntu/linux-fips<6.8.0-78.78+fips1
6.8.0-78.78+fips1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 6.6.82.1-1
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 5.15.180.1-1
  3. Upgrade

    Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.

    Fixed in 4.4.0-1148.154
  4. Upgrade

    Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.

    Fixed in 4.15.0-1193.208~14.04.1
  5. Upgrade

    Upgrade ubuntu/linux-lts-xenial to a version that resolves this vulnerability.

    Fixed in 4.4.0-273.307~14.04.1
  6. Upgrade

    Upgrade ubuntu/linux to a version that resolves this vulnerability.

    Fixed in 4.4.0-273.307
  7. Upgrade

    Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.

    Fixed in 4.4.0-1186.201
  8. Upgrade

    Upgrade ubuntu/linux-aws-hwe to a version that resolves this vulnerability.

    Fixed in 4.15.0-1185.198~16.04.1
  9. Upgrade

    Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.

    Fixed in 4.15.0-1193.208~16.04.1
  10. Upgrade

    Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.

    Fixed in 4.15.0-1178.195~16.04.1
  11. Upgrade

    Upgrade ubuntu/linux-hwe to a version that resolves this vulnerability.

    Fixed in 4.15.0-242.254~16.04.1
  12. Upgrade

    Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.

    Fixed in 4.4.0-1149.160
  13. Upgrade

    Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.

    Fixed in 4.15.0-1148.159~16.04.1
  14. Upgrade

    Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.

    Fixed in 4.4.0-1119.126
  15. Upgrade

    Upgrade ubuntu/linux to a version that resolves this vulnerability.

    Fixed in 4.15.0-242.254
  16. Upgrade

    Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.

    Fixed in 4.15.0-1185.198
  17. Upgrade

    Upgrade ubuntu/linux-aws-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1151.161~18.04.1
  18. Upgrade

    Upgrade ubuntu/linux-azure-4.15 to a version that resolves this vulnerability.

    Fixed in 4.15.0-1193.208
  19. Upgrade

    Upgrade ubuntu/linux-azure-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1154.161~18.04.1
  20. Upgrade

    Upgrade ubuntu/linux-gcp-4.15 to a version that resolves this vulnerability.

    Fixed in 4.15.0-1178.195
  21. Upgrade

    Upgrade ubuntu/linux-gcp-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1154.163~18.04.1
  22. Upgrade

    Upgrade ubuntu/linux-hwe-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-222.242~18.04.1
  23. Upgrade

    Upgrade ubuntu/linux-ibm-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1097.102~18.04.1
  24. Upgrade

    Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.

    Fixed in 4.15.0-1168.173
  25. Upgrade

    Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.

    Fixed in 4.15.0-1147.158
  26. Upgrade

    Upgrade ubuntu/linux-oracle-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1149.159~18.04.1
  27. Upgrade

    Upgrade ubuntu/linux-raspi-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1134.147~18.04.1
  28. Upgrade

    Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.

    Fixed in 4.15.0-2123.129
  29. Upgrade

    Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.

    Fixed in 4.15.0-2102.108
  30. Upgrade

    Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.

    Fixed in 4.15.0-1140.151
  31. Upgrade

    Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.

    Fixed in 4.15.0-2086.92
  32. Upgrade

    Upgrade ubuntu/linux-aws-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-1084.91~20.04.1
  33. Upgrade

    Upgrade ubuntu/linux-azure-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-1089.98~20.04.1
  34. Upgrade

    Upgrade ubuntu/linux-gcp-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-1083.92~20.04.1
  35. Upgrade

    Upgrade ubuntu/linux-ibm-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-1076.79~20.04.1
  36. Upgrade

    Upgrade ubuntu/linux-intel-iotg-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-1079.85~20.04.1
  37. Upgrade

    Upgrade ubuntu/linux-lowlatency-hwe-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-140.150~20.04.1
  38. Upgrade

    Upgrade ubuntu/linux-oracle-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-1081.87~20.04.1
  39. Upgrade

    Upgrade ubuntu/linux-riscv-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-1079.83~20.04.1
  40. Upgrade

    Upgrade ubuntu/linux to a version that resolves this vulnerability.

    Fixed in 5.4.0-222.242
  41. Upgrade

    Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.

    Fixed in 5.4.0-1151.161
  42. Upgrade

    Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.

    Fixed in 5.4.0-1154.161
  43. Upgrade

    Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.

    Fixed in 5.4.0-1110.117
  44. Upgrade

    Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.

    Fixed in 5.4.0-1154.163
  45. Upgrade

    Upgrade ubuntu/linux-hwe-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-142.152~20.04.1
  46. Upgrade

    Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.

    Fixed in 5.4.0-1097.102
  47. Upgrade

    Upgrade ubuntu/linux-iot to a version that resolves this vulnerability.

    Fixed in 5.4.0-1055.58
  48. Upgrade

    Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.

    Fixed in 5.4.0-1138.147
  49. Upgrade

    Upgrade ubuntu/linux-nvidia-tegra-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-1039.39~20.04.1
  50. Upgrade

    Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.

    Fixed in 5.4.0-1149.159
  51. Upgrade

    Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.

    Fixed in 5.4.0-1134.147
  52. Upgrade

    Upgrade ubuntu/linux-xilinx-zynqmp to a version that resolves this vulnerability.

    Fixed in 5.4.0-1069.73
  53. Upgrade

    Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.

    Fixed in 5.4.0-1151.161+fips1
  54. Upgrade

    Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.

    Fixed in 5.4.0-1155.162+fips1
  55. Upgrade

    Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.

    Fixed in 5.4.0-1125.135
  56. Upgrade

    Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.

    Fixed in 5.4.0-1154.163+fips1
  57. Upgrade

    Upgrade ubuntu/linux to a version that resolves this vulnerability.

    Fixed in 5.15.0-140.150
  58. Upgrade

    Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.

    Fixed in 5.15.0-1084.91
  59. Upgrade

    Upgrade ubuntu/linux-aws-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1035.37~22.04.1
  60. Upgrade

    Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.

    Fixed in 5.15.0-1089.98
  61. Upgrade

    Upgrade ubuntu/linux-azure-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1034.39~22.04.1
  62. Upgrade

    Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.

    Fixed in 5.15.0-1089.98.1
  63. Upgrade

    Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.

    Fixed in 5.15.0-1083.92
  64. Upgrade

    Upgrade ubuntu/linux-gcp-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1036.38~22.04.1
  65. Upgrade

    Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.

    Fixed in 5.15.0-1081.87
  66. Upgrade

    Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.

    Fixed in 5.15.0-1066.74
  67. Upgrade

    Upgrade ubuntu/linux-hwe-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-78.78~22.04.1
  68. Upgrade

    Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.

    Fixed in 5.15.0-1076.79
  69. Upgrade

    Upgrade ubuntu/linux-ibm-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1033.33~22.04.1
  70. Upgrade

    Upgrade ubuntu/linux-intel-iotg to a version that resolves this vulnerability.

    Fixed in 5.15.0-1079.85
  71. Upgrade

    Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.

    Fixed in 5.15.0-1080.85
  72. Upgrade

    Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.

    Fixed in 5.15.0-140.150
  73. Upgrade

    Upgrade ubuntu/linux-lowlatency-hwe-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-78.78.1~22.04.1
  74. Upgrade

    Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.

    Fixed in 5.15.0-1078.79
  75. Upgrade

    Upgrade ubuntu/linux-nvidia-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1035.38~22.04.1
  76. Upgrade

    Upgrade ubuntu/linux-nvidia-tegra to a version that resolves this vulnerability.

    Fixed in 5.15.0-1037.37
  77. Upgrade

    Upgrade ubuntu/linux-nvidia-tegra-igx to a version that resolves this vulnerability.

    Fixed in 5.15.0-1026.26
  78. Upgrade

    Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.

    Fixed in 5.15.0-1081.87
  79. Upgrade

    Upgrade ubuntu/linux-oracle-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1032.33~22.04.1
  80. Upgrade

    Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.

    Fixed in 5.15.0-1078.81
  81. Upgrade

    Upgrade ubuntu/linux-riscv-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-78.78~22.04.1
  82. Upgrade

    Upgrade ubuntu/linux-xilinx-zynqmp to a version that resolves this vulnerability.

    Fixed in 5.15.0-1050.54
  83. Upgrade

    Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.

    Fixed in 5.15.0-1066.68
  84. Upgrade

    Upgrade ubuntu/linux-intel-iot-realtime to a version that resolves this vulnerability.

    Fixed in 5.15.0-1077.79
  85. Upgrade

    Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.

    Fixed in 5.15.0-1084.93
  86. Upgrade

    Upgrade ubuntu/linux-realtime-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.1-1030.31~22.04.1
  87. Upgrade

    Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.

    Fixed in 5.15.0-1084.91+fips1
  88. Upgrade

    Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.

    Fixed in 5.15.0-1089.98+fips1
  89. Upgrade

    Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.

    Fixed in 5.15.0-140.150+fips1
  90. Upgrade

    Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.

    Fixed in 5.15.0-1083.92+fips1
  91. Upgrade

    Upgrade ubuntu/linux to a version that resolves this vulnerability.

    Fixed in 6.8.0-78.78
  92. Upgrade

    Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.

    Fixed in 6.8.0-1035.37
  93. Upgrade

    Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.

    Fixed in 6.8.0-1034.39
  94. Upgrade

    Upgrade ubuntu/linux-azure-6.11 to a version that resolves this vulnerability.

    Fixed in 6.11.0-1015.15~24.04.1
  95. Upgrade

    Upgrade ubuntu/linux-azure-nvidia to a version that resolves this vulnerability.

    Fixed in 6.8.0-1022.23
  96. Upgrade

    Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.

    Fixed in 6.8.0-1036.38
  97. Upgrade

    Upgrade ubuntu/linux-gcp-6.11 to a version that resolves this vulnerability.

    Fixed in 6.11.0-1015.15~24.04.1
  98. Upgrade

    Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.

    Fixed in 6.8.0-1032.36
  99. Upgrade

    Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.

    Fixed in 6.8.0-1019.21
  100. Upgrade

    Upgrade ubuntu/linux-hwe-6.11 to a version that resolves this vulnerability.

    Fixed in 6.11.0-26.26~24.04.1
  101. Upgrade

    Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.

    Fixed in 6.8.0-1033.33
  102. Upgrade

    Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.

    Fixed in 6.8.0-78.78.1
  103. Upgrade

    Upgrade ubuntu/linux-lowlatency-hwe-6.11 to a version that resolves this vulnerability.

    Fixed in 6.11.0-1014.15~24.04.1
  104. Upgrade

    Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.

    Fixed in 6.8.0-1035.38
  105. Upgrade

    Upgrade ubuntu/linux-nvidia-6.11 to a version that resolves this vulnerability.

    Fixed in 6.11.0-1010.10
  106. Upgrade

    Upgrade ubuntu/linux-nvidia-lowlatency to a version that resolves this vulnerability.

    Fixed in 6.8.0-1035.38.1
  107. Upgrade

    Upgrade ubuntu/linux-nvidia-tegra to a version that resolves this vulnerability.

    Fixed in 6.8.0-1009.9
  108. Upgrade

    Upgrade ubuntu/linux-oem-6.11 to a version that resolves this vulnerability.

    Fixed in 6.11.0-1022.22
  109. Upgrade

    Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.

    Fixed in 6.8.0-1032.33
  110. Upgrade

    Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.

    Fixed in 6.8.0-1035.39
  111. Upgrade

    Upgrade ubuntu/linux-xilinx to a version that resolves this vulnerability.

    Fixed in 6.8.0-1017.18
  112. Upgrade

    Upgrade ubuntu/linux-raspi-realtime to a version that resolves this vulnerability.

    Fixed in 6.8.0-2028.29
  113. Upgrade

    Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.

    Fixed in 6.8.1-1030.31
  114. Upgrade

    Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.

    Fixed in 6.8.0-78.78+fips1

Event History

Feb 27, 2025
CVE Published
via MITRE·02:18 AM
Data Sourced
via MITRE·02:18 AM
DescriptionSeverity
Data Sourced
via Red Hat·03:04 AM
DescriptionSeverityAffected Software
Data Sourced
via OSV·03:15 AM
DescriptionSeverityAffected Software
Data Sourced
via NVD·03:15 AM
RemedyDescriptionSeverityWeaknessAffected Software
Apr 9, 2025
Data Sourced
via Microsoft·07:00 AM
DescriptionSeverityWeaknessAffected Software
Jul 8, 2026
Data Sourced
via IBM·12:00 AM
DescriptionAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Frequently Asked Questions

1

What is the severity of CVE-2025-21796?

CVE-2025-21796 has a moderate severity level due to its impact on access control list (ACL) handling in the Linux kernel.

2

How do I fix CVE-2025-21796?

To fix CVE-2025-21796, update to the latest version of the Linux kernel that includes the patch for this vulnerability.

3

What systems are affected by CVE-2025-21796?

CVE-2025-21796 affects various distributions of the Linux kernel that utilize the nfsd component.

4

What type of vulnerability is CVE-2025-21796?

CVE-2025-21796 is classified as an access control vulnerability related to improper handling of ACLs.

5

Is CVE-2025-21796 exploitable remotely?

CVE-2025-21796 could potentially be exploited remotely if the affected system's NFS service is exposed to untrusted networks.

Company

Resources

Contact

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