UBUNTU-CVE-2025-38051: Use After Free

Q: Who is exposed to this issue?

Systems running the listed Ubuntu Linux kernel packages are in scope when they use the SMB/CIFS client and perform directory reads on SMB/CIFS mounts. The issue is in the client-side CIFS directory-entry handling path.

Q: What conditions are needed to trigger the vulnerability?

Exploitation requires local access with low privileges and a race during concurrent directory-read activity. The affected path is cifs_readdir/cifs_fill_dirent, where a response buffer can be accessed after release.

Q: What is the likely impact?

The vulnerability is a use-after-free that can cause a kernel memory-safety failure during CIFS directory enumeration. The supplied metrics indicate low confidentiality impact and high availability impact, with no integrity impact.

Q: How can I determine whether a system may be affected?

Check whether the system runs one of the listed Ubuntu kernel packages and has SMB/CIFS client mounts in use. The provided diagnostic evidence is a KASAN slab-use-after-free report referencing cifs_fill_dirent during getdents/iterate_dir activity.

Published Jun 18, 2025

Updated

In the Linux kernel, the following vulnerability has been resolved: smb: client: Fix use-after-free in cifsfilldirent There is a race condition in the readdir concurrency process, which may access the rsp buffer after it has been released, triggering the following KASAN warning. ================================================================== BUG: KASAN: slab-use-after-free in cifsfilldirent+0xb03/0xb60 [cifs] Read of size 4 at addr ffff8880099b819c by task a.out/342975 CPU: 2 UID: 0 PID: 342975 Comm: a.out Not tainted 6.15.0-rc6+ #240 PREEMPT(full) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 Call Trace: <TASK> dumpstacklvl+0x53/0x70 printreport+0xce/0x640 kasanreport+0xb8/0xf0 cifsfilldirent+0xb03/0xb60 [cifs] cifsreaddir+0x12cb/0x3190 [cifs] iteratedir+0x1a1/0x520 x64sysgetdents+0x134/0x220 dosyscall64+0x4b/0x110 entrySYSCALL64afterhwframe+0x76/0x7e RIP: 0033:0x7f996f64b9f9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0d f7 c3 0c 00 f7 d8 64 89 8 RSP: 002b:00007f996f53de78 EFLAGS: 00000207 ORIGRAX: 000000000000004e RAX: ffffffffffffffda RBX: 00007f996f53ecdc RCX: 00007f996f64b9f9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007f996f53dea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000207 R12: ffffffffffffff88 R13: 0000000000000000 R14: 00007ffc8cd9a500 R15: 00007f996f51e000 </TASK> Allocated by task 408: kasansavestack+0x20/0x40 kasansavetrack+0x14/0x30 kasanslaballoc+0x6e/0x70 kmemcacheallocnoprof+0x117/0x3d0 mempoolallocnoprof+0xf2/0x2c0 cifsbufget+0x36/0x80 [cifs] allocatebuffers+0x1d2/0x330 [cifs] cifsdemultiplexthread+0x22b/0x2690 [cifs] kthread+0x394/0x720 retfromfork+0x34/0x70 retfromforkasm+0x1a/0x30 Freed by task 342979: kasansavestack+0x20/0x40 kasansavetrack+0x14/0x30 kasansavefreeinfo+0x3b/0x60 kasanslabfree+0x37/0x50 kmemcachefree+0x2b8/0x500 cifsbufrelease+0x3c/0x70 [cifs] cifsreaddir+0x1c97/0x3190 [cifs] iteratedir+0x1a1/0x520 x64sysgetdents64+0x134/0x220 dosyscall64+0x4b/0x110 entrySYSCALL64afterhwframe+0x76/0x7e The buggy address belongs to the object at ffff8880099b8000 which belongs to the cache cifsrequest of size 16588 The buggy address is located 412 bytes inside of freed 16588-byte region [ffff8880099b8000, ffff8880099bc0cc) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x99b8 head: order:3 mapcount:0 entiremapcount:0 nrpagesmapped:0 pincount:0 anon flags: 0x80000000000040(head|node=0|zone=1) pagetype: f5(slab) raw: 0080000000000040 ffff888001e03400 0000000000000000 dead000000000001 raw: 0000000000000000 0000000000010001 00000000f5000000 0000000000000000 head: 0080000000000040 ffff888001e03400 0000000000000000 dead000000000001 head: 0000000000000000 0000000000010001 00000000f5000000 0000000000000000 head: 0080000000000003 ffffea0000266e01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880099b8080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880099b8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880099b8180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880099b8200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880099b8280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== POC is available in the link [1]. The problem triggering process is as follows: Process 1 Process 2 ----------------------------------- ---truncated---

Affected Software

222 affected componentsFixes available

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-azure*

ubuntu/linux-lts-xenial*

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-aws-hwe*

ubuntu/linux-azure*

ubuntu/linux-gcp*

ubuntu/linux-hwe*

ubuntu/linux-hwe-edge*

ubuntu/linux-kvm*

ubuntu/linux-oracle*

ubuntu/linux-fips*

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-aws-5.0*

ubuntu/linux-aws-5.3*

ubuntu/linux-aws-5.4*

ubuntu/linux-azure*

ubuntu/linux-azure-4.15*

ubuntu/linux-azure-5.3*

ubuntu/linux-azure-5.4*

ubuntu/linux-azure-edge*

ubuntu/linux-gcp*

ubuntu/linux-gcp-4.15*

ubuntu/linux-gcp-5.3*

ubuntu/linux-gcp-5.4*

ubuntu/linux-gke-4.15*

ubuntu/linux-gke-5.4*

ubuntu/linux-gkeop-5.4*

ubuntu/linux-hwe*

ubuntu/linux-hwe-5.4*

ubuntu/linux-hwe-edge*

ubuntu/linux-ibm-5.4*

ubuntu/linux-kvm*

ubuntu/linux-oem*

ubuntu/linux-oracle*

ubuntu/linux-oracle-5.0*

ubuntu/linux-oracle-5.3*

ubuntu/linux-oracle-5.4*

ubuntu/linux-raspi-5.4*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-aws-5.11*

ubuntu/linux-aws-5.13*

ubuntu/linux-aws-5.15<5.15.0-1090.97~20.04.1

5.15.0-1090.97~20.04.1

ubuntu/linux-aws-5.8*

ubuntu/linux-azure*

ubuntu/linux-azure-5.11*

ubuntu/linux-azure-5.13*

ubuntu/linux-azure-5.15<5.15.0-1094.103~20.04.1

5.15.0-1094.103~20.04.1

ubuntu/linux-azure-5.8*

ubuntu/linux-azure-fde*

ubuntu/linux-bluefield*

ubuntu/linux-gcp*

ubuntu/linux-gcp-5.11*

ubuntu/linux-gcp-5.13*

ubuntu/linux-gcp-5.15<5.15.0-1090.99~20.04.1

5.15.0-1090.99~20.04.1

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<5.15.0-152.162~20.04.1

5.15.0-152.162~20.04.1

ubuntu/linux-hwe-5.8*

ubuntu/linux-ibm*

ubuntu/linux-ibm-5.15<5.15.0-1083.86~20.04.1

5.15.0-1083.86~20.04.1

ubuntu/linux-intel-5.13*

ubuntu/linux-intel-iotg-5.15<5.15.0-1085.91~20.04.1

5.15.0-1085.91~20.04.1

ubuntu/linux-iot*

ubuntu/linux-kvm*

ubuntu/linux-lowlatency-hwe-5.15<5.15.0-152.162~20.04.1

5.15.0-152.162~20.04.1

ubuntu/linux-nvidia-tegra-5.15<5.15.0-1043.43~20.04.1

5.15.0-1043.43~20.04.1

ubuntu/linux-oem-5.10*

ubuntu/linux-oem-5.13*

ubuntu/linux-oem-5.6*

ubuntu/linux-oracle*

ubuntu/linux-oracle-5.11*

ubuntu/linux-oracle-5.13*

ubuntu/linux-oracle-5.15<5.15.0-1088.94~20.04.1

5.15.0-1088.94~20.04.1

ubuntu/linux-oracle-5.8*

ubuntu/linux-raspi*

ubuntu/linux-raspi2*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.11*

ubuntu/linux-riscv-5.15<5.15.0-1085.89~20.04.1

5.15.0-1085.89~20.04.1

ubuntu/linux-riscv-5.8*

ubuntu/linux-xilinx-zynqmp*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux<5.15.0-152.162

5.15.0-152.162

ubuntu/linux-allwinner-5.19*

ubuntu/linux-aws<5.15.0-1090.97

5.15.0-1090.97

ubuntu/linux-aws-5.19*

ubuntu/linux-aws-6.2*

ubuntu/linux-aws-6.5*

ubuntu/linux-aws-6.8<6.8.0-1046.49~22.04.1

6.8.0-1046.49~22.04.1

ubuntu/linux-azure<5.15.0-1094.103

5.15.0-1094.103

ubuntu/linux-azure-5.19*

ubuntu/linux-azure-6.2*

ubuntu/linux-azure-6.5*

ubuntu/linux-azure-6.8<6.8.0-1051.57~22.04.1

6.8.0-1051.57~22.04.1

ubuntu/linux-azure-fde<5.15.0-1094.103.1

5.15.0-1094.103.1

ubuntu/linux-azure-fde-5.19*

ubuntu/linux-azure-fde-6.2*

ubuntu/linux-azure-fde-6.8<6.8.0-1046.53~22.04.1

6.8.0-1046.53~22.04.1

ubuntu/linux-gcp<5.15.0-1090.99

5.15.0-1090.99

ubuntu/linux-gcp-5.19*

ubuntu/linux-gcp-6.2*

ubuntu/linux-gcp-6.5*

ubuntu/linux-gcp-6.8<6.8.0-1047.50~22.04.2

6.8.0-1047.50~22.04.2

ubuntu/linux-gke<5.15.0-1087.93

5.15.0-1087.93

ubuntu/linux-gkeop<5.15.0-1073.81

5.15.0-1073.81

ubuntu/linux-hwe-5.19*

ubuntu/linux-hwe-6.2*

ubuntu/linux-hwe-6.5*

ubuntu/linux-hwe-6.8<6.8.0-100.100~22.04.1

6.8.0-100.100~22.04.1

ubuntu/linux-ibm<5.15.0-1084.87

5.15.0-1084.87

ubuntu/linux-ibm-6.8<6.8.0-1044.44~22.04.1

6.8.0-1044.44~22.04.1

ubuntu/linux-intel-iot-realtime*

ubuntu/linux-intel-iotg<5.15.0-1085.91

5.15.0-1085.91

ubuntu/linux-kvm<5.15.0-1086.91

5.15.0-1086.91

ubuntu/linux-lowlatency<5.15.0-152.162

5.15.0-152.162

ubuntu/linux-lowlatency-hwe-5.19*

ubuntu/linux-lowlatency-hwe-6.2*

ubuntu/linux-lowlatency-hwe-6.5*

ubuntu/linux-lowlatency-hwe-6.8<6.8.0-100.100.1~22.04.1

6.8.0-100.100.1~22.04.1

ubuntu/linux-nvidia<5.15.0-1085.86

5.15.0-1085.86

ubuntu/linux-nvidia-6.2*

ubuntu/linux-nvidia-6.5*

ubuntu/linux-nvidia-6.8<6.8.0-1046.49~22.04.1

6.8.0-1046.49~22.04.1

ubuntu/linux-nvidia-tegra<5.15.0-1043.43

5.15.0-1043.43

ubuntu/linux-nvidia-tegra-igx<5.15.0-1032.32

5.15.0-1032.32

ubuntu/linux-oem-5.17*

ubuntu/linux-oem-6.0*

ubuntu/linux-oem-6.1*

ubuntu/linux-oem-6.5*

ubuntu/linux-oracle<5.15.0-1088.94

5.15.0-1088.94

ubuntu/linux-oracle-6.5*

ubuntu/linux-oracle-6.8<6.8.0-1043.44~22.04.1

6.8.0-1043.44~22.04.1

ubuntu/linux-raspi<5.15.0-1084.87

5.15.0-1084.87

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-riscv-6.5*

ubuntu/linux-riscv-6.8<6.8.0-100.100~22.04.1

6.8.0-100.100~22.04.1

ubuntu/linux-starfive-5.19*

ubuntu/linux-starfive-6.2*

ubuntu/linux-starfive-6.5*

ubuntu/linux-xilinx-zynqmp<5.15.0-1054.58

5.15.0-1054.58

ubuntu/linux-bluefield<5.15.0-1074.76

5.15.0-1074.76

ubuntu/linux-intel-iot-realtime<5.15.0-1083.85

5.15.0-1083.85

ubuntu/linux-realtime<5.15.0-1090.99

5.15.0-1090.99

ubuntu/linux-realtime-6.8<6.8.1-1041.42~22.04.1

6.8.1-1041.42~22.04.1

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips<5.15.0-1090.97+fips1

5.15.0-1090.97+fips1

ubuntu/linux-azure-fips<5.15.0-1094.103+fips1

5.15.0-1094.103+fips1

ubuntu/linux-fips<5.15.0-152.162+fips1

5.15.0-152.162+fips1

ubuntu/linux-gcp-fips<5.15.0-1090.99+fips1

5.15.0-1090.99+fips1

ubuntu/linux<6.8.0-100.100

6.8.0-100.100

ubuntu/linux-aws<6.8.0-1046.49

6.8.0-1046.49

ubuntu/linux-aws-6.14<6.14.0-1013.13~24.04.1

6.14.0-1013.13~24.04.1

ubuntu/linux-azure<6.8.0-1046.52

6.8.0-1046.52

ubuntu/linux-azure-6.11*

ubuntu/linux-azure-fde<6.8.0-1046.53

6.8.0-1046.53

ubuntu/linux-azure-nvidia<6.8.0-1039.42

6.8.0-1039.42

ubuntu/linux-azure-nvidia-6.14<6.14.0-1007.7

6.14.0-1007.7

ubuntu/linux-gcp<6.8.0-1047.50

6.8.0-1047.50

ubuntu/linux-gcp-6.11*

ubuntu/linux-gcp-6.14<6.14.0-1016.17~24.04.1

6.14.0-1016.17~24.04.1

ubuntu/linux-gke<6.8.0-1043.48

6.8.0-1043.48

ubuntu/linux-gkeop<6.8.0-1030.33

6.8.0-1030.33

ubuntu/linux-hwe-6.11*

ubuntu/linux-ibm<6.8.0-1044.44

6.8.0-1044.44

ubuntu/linux-intel*

ubuntu/linux-lowlatency<6.8.0-100.100.1

6.8.0-100.100.1

ubuntu/linux-lowlatency-hwe-6.11*

ubuntu/linux-nvidia<6.8.0-1046.49

6.8.0-1046.49

ubuntu/linux-nvidia-6.11*

ubuntu/linux-nvidia-lowlatency<6.8.0-1046.49.1

6.8.0-1046.49.1

ubuntu/linux-nvidia-tegra<6.8.0-1020.20

6.8.0-1020.20

ubuntu/linux-oem-6.11*

ubuntu/linux-oem-6.14<6.14.0-1012.12

6.14.0-1012.12

ubuntu/linux-oem-6.8*

ubuntu/linux-oracle<6.8.0-1043.44

6.8.0-1043.44

ubuntu/linux-oracle-6.14<6.14.0-1013.13~24.04.1

6.14.0-1013.13~24.04.1

ubuntu/linux-raspi<6.8.0-1047.51

6.8.0-1047.51

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-6.14<6.14.0-32.32.1~24.04.1

6.14.0-32.32.1~24.04.1

ubuntu/linux-xilinx<6.8.0-1023.24

6.8.0-1023.24

ubuntu/linux-bluefield<6.8.0-1016.20

6.8.0-1016.20

ubuntu/linux-raspi-realtime<6.8.0-2037.38

6.8.0-2037.38

ubuntu/linux-realtime<6.8.1-1041.42

6.8.1-1041.42

ubuntu/linux-realtime-6.14<6.14.0-1012.12~24.04.1

6.14.0-1012.12~24.04.1

ubuntu/linux-aws-fips<6.8.0-1046.49+fips1

6.8.0-1046.49+fips1

ubuntu/linux-azure-fips<6.8.0-1046.52+fips1

6.8.0-1046.52+fips1

ubuntu/linux-fips<6.8.0-100.100+fips1

6.8.0-100.100+fips1

ubuntu/linux-gcp-fips<6.8.0-1047.50+fips1

6.8.0-1047.50+fips1

ubuntu/linux-azure-fde*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade ubuntu/linux-aws-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1090.97~20.04.1
Upgrade
Upgrade ubuntu/linux-azure-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1094.103~20.04.1
Upgrade
Upgrade ubuntu/linux-gcp-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1090.99~20.04.1
Upgrade
Upgrade ubuntu/linux-hwe-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-152.162~20.04.1
Upgrade
Upgrade ubuntu/linux-ibm-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1083.86~20.04.1
Upgrade
Upgrade ubuntu/linux-intel-iotg-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1085.91~20.04.1
Upgrade
Upgrade ubuntu/linux-lowlatency-hwe-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-152.162~20.04.1
Upgrade
Upgrade ubuntu/linux-nvidia-tegra-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1043.43~20.04.1
Upgrade
Upgrade ubuntu/linux-oracle-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1088.94~20.04.1
Upgrade
Upgrade ubuntu/linux-riscv-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1085.89~20.04.1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 5.15.0-152.162
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 5.15.0-1090.97
Upgrade
Upgrade ubuntu/linux-aws-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1046.49~22.04.1
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 5.15.0-1094.103
Upgrade
Upgrade ubuntu/linux-azure-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1051.57~22.04.1
Upgrade
Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 5.15.0-1094.103.1
Upgrade
Upgrade ubuntu/linux-azure-fde-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1046.53~22.04.1
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 5.15.0-1090.99
Upgrade
Upgrade ubuntu/linux-gcp-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1047.50~22.04.2
Upgrade
Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 5.15.0-1087.93
Upgrade
Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.
Fixed in 5.15.0-1073.81
Upgrade
Upgrade ubuntu/linux-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-100.100~22.04.1
Upgrade
Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 5.15.0-1084.87
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Upgrade ubuntu/linux-ibm-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1044.44~22.04.1
Upgrade
Upgrade ubuntu/linux-intel-iotg to a version that resolves this vulnerability.
Fixed in 5.15.0-1085.91
Upgrade
Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.
Fixed in 5.15.0-1086.91
Upgrade
Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.
Fixed in 5.15.0-152.162
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Upgrade ubuntu/linux-lowlatency-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-100.100.1~22.04.1
Upgrade
Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.
Fixed in 5.15.0-1085.86
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Upgrade ubuntu/linux-nvidia-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1046.49~22.04.1
Upgrade
Upgrade ubuntu/linux-nvidia-tegra to a version that resolves this vulnerability.
Fixed in 5.15.0-1043.43
Upgrade
Upgrade ubuntu/linux-nvidia-tegra-igx to a version that resolves this vulnerability.
Fixed in 5.15.0-1032.32
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 5.15.0-1088.94
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Upgrade ubuntu/linux-oracle-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1043.44~22.04.1
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Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.
Fixed in 5.15.0-1084.87
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Upgrade ubuntu/linux-riscv-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-100.100~22.04.1
Upgrade
Upgrade ubuntu/linux-xilinx-zynqmp to a version that resolves this vulnerability.
Fixed in 5.15.0-1054.58
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Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.
Fixed in 5.15.0-1074.76
Upgrade
Upgrade ubuntu/linux-intel-iot-realtime to a version that resolves this vulnerability.
Fixed in 5.15.0-1083.85
Upgrade
Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 5.15.0-1090.99
Upgrade
Upgrade ubuntu/linux-realtime-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.1-1041.42~22.04.1
Upgrade
Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1090.97+fips1
Upgrade
Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1094.103+fips1
Upgrade
Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-152.162+fips1
Upgrade
Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1090.99+fips1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 6.8.0-100.100
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 6.8.0-1046.49
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Fixed in 6.14.0-1013.13~24.04.1
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Fixed in 6.8.0-1046.52
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Fixed in 6.8.0-1046.53
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Fixed in 6.8.0-1039.42
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Fixed in 6.14.0-1007.7
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Fixed in 6.8.0-1047.50
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Fixed in 6.14.0-1016.17~24.04.1
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Fixed in 6.8.0-1043.48
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Fixed in 6.8.0-1030.33
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Fixed in 6.8.0-1044.44
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Fixed in 6.8.0-100.100.1
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Fixed in 6.8.0-1046.49
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Fixed in 6.8.0-1046.49.1
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Fixed in 6.8.0-1020.20
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Fixed in 6.14.0-1012.12
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Fixed in 6.8.0-1043.44
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Fixed in 6.14.0-1013.13~24.04.1
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Fixed in 6.8.0-1047.51
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Fixed in 6.14.0-32.32.1~24.04.1
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Fixed in 6.8.0-1023.24
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Fixed in 6.8.0-1016.20
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Fixed in 6.8.0-2037.38
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Fixed in 6.8.1-1041.42
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Fixed in 6.14.0-1012.12~24.04.1
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Fixed in 6.8.0-1046.49+fips1
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Fixed in 6.8.0-1046.52+fips1
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Fixed in 6.8.0-100.100+fips1
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Fixed in 6.8.0-1047.50+fips1

Event History

Jun 18, 2025

CVE Published

via OSV·10:15 AM

Data Sourced

via OSV·10:15 AM

DescriptionSeverityAffected Software

Frequently Asked Questions

Who is exposed to this issue?

Systems running the listed Ubuntu Linux kernel packages are in scope when they use the SMB/CIFS client and perform directory reads on SMB/CIFS mounts. The issue is in the client-side CIFS directory-entry handling path.

What conditions are needed to trigger the vulnerability?

Exploitation requires local access with low privileges and a race during concurrent directory-read activity. The affected path is cifs_readdir/cifs_fill_dirent, where a response buffer can be accessed after release.

What is the likely impact?

The vulnerability is a use-after-free that can cause a kernel memory-safety failure during CIFS directory enumeration. The supplied metrics indicate low confidentiality impact and high availability impact, with no integrity impact.

How can I determine whether a system may be affected?

Check whether the system runs one of the listed Ubuntu kernel packages and has SMB/CIFS client mounts in use. The provided diagnostic evidence is a KASAN slab-use-after-free report referencing cifs_fill_dirent during getdents/iterate_dir activity.

UBUNTU-CVE-2025-38051: Use After Free

Affected Software

Remediation

Event History

Frequently Asked Questions

Who is exposed to this issue?

What conditions are needed to trigger the vulnerability?

What is the likely impact?

How can I determine whether a system may be affected?

Company

Resources

Contact

Frequently Asked Questions

Who is exposed to this issue?

What conditions are needed to trigger the vulnerability?

What is the likely impact?

How can I determine whether a system may be affected?