UBUNTU-CVE-2025-68366: Use After Free

Q: What sequence triggers the use-after-free condition?

The issue occurs when NBD_CMD_CONNECT races with NBD_CLEAR_SOCK during nbd_genl_connect. The reported sequence drops the configuration reference count to zero during close, after which nbd_genl_connect attempts to increment it.

Q: How can I identify a system that has encountered this issue?

Look for a kernel warning stating "refcount_t: addition on 0; use-after-free" with nbd_genl_connect in the stack trace. The warning may also include calls through genl_family_rcv_msg_doit and genl_rcv_msg.

Published Dec 24, 2025

Updated

In the Linux kernel, the following vulnerability has been resolved: nbd: defer config unlock in nbdgenlconnect There is one use-after-free warning when running NBDCMDCONNECT and NBDCLEARSOCK: nbdgenlconnect nbdallocandinitconfig // configrefs=1 nbdstartdevice // configrefs=2 set NBDRTHASCONFIGREF open nbd // configrefs=3 recvwork done // configrefs=2 NBDCLEARSOCK // configrefs=1 close nbd // configrefs=0 refcountinc -> uaf ------------[ cut here ]------------ refcountt: addition on 0; use-after-free. WARNING: CPU: 24 PID: 1014 at lib/refcount.c:25 refcountwarnsaturate+0x12e/0x290 nbdgenlconnect+0x16d0/0x1ab0 genlfamilyrcvmsgdoit+0x1f3/0x310 genlrcvmsg+0x44a/0x790 The issue can be easily reproduced by adding a small delay before refcountinc(&nbd->configrefs) in nbdgenlconnect(): mutexunlock(&nbd->configlock); if (!ret) { setbit(NBDRTHASCONFIGREF, &config->runtimeflags); + printk("before sleep\n"); + mdelay(5 1000); + printk("after sleep\n"); refcountinc(&nbd->configrefs); nbdconnectreply(info, nbd->index); }

Affected Software

234 affected componentsFixes available

ubuntu/linux-azure*

ubuntu/linux-aws-hwe*

ubuntu/linux-azure*

ubuntu/linux-gcp*

ubuntu/linux-hwe*

ubuntu/linux-hwe-edge*

ubuntu/linux-oracle*

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<5.15.0-1103.110~20.04.1

5.15.0-1103.110~20.04.1

ubuntu/linux-aws-5.8*

ubuntu/linux-azure*

ubuntu/linux-azure-5.11*

ubuntu/linux-azure-5.13*

ubuntu/linux-azure-5.15<5.15.0-1110.119~20.04.1

5.15.0-1110.119~20.04.1

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<5.15.0-1103.112~20.04.1

5.15.0-1103.112~20.04.1

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<5.15.0-173.183~20.04.1

5.15.0-173.183~20.04.1

ubuntu/linux-hwe-5.8*

ubuntu/linux-ibm*

ubuntu/linux-ibm-5.15<5.15.0-1097.100~20.04.1

5.15.0-1097.100~20.04.1

ubuntu/linux-intel-5.13*

ubuntu/linux-intel-iotg-5.15<5.15.0-1098.104~20.04.1

5.15.0-1098.104~20.04.1

ubuntu/linux-iot*

ubuntu/linux-kvm*

ubuntu/linux-lowlatency-hwe-5.15<5.15.0-173.183~20.04.1

5.15.0-173.183~20.04.1

ubuntu/linux-nvidia-tegra-5.15<5.15.0-1055.55~20.04.1

5.15.0-1055.55~20.04.1

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<5.15.0-1100.106~20.04.1

5.15.0-1100.106~20.04.1

ubuntu/linux-oracle-5.8*

ubuntu/linux-raspi*

ubuntu/linux-raspi2*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.11*

ubuntu/linux-riscv-5.15<5.15.0-1097.101~20.04.1

5.15.0-1097.101~20.04.1

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<5.15.0-173.183

5.15.0-173.183

ubuntu/linux-allwinner-5.19*

ubuntu/linux-aws<5.15.0-1103.110

5.15.0-1103.110

ubuntu/linux-aws-5.19*

ubuntu/linux-aws-6.2*

ubuntu/linux-aws-6.5*

ubuntu/linux-aws-6.8<6.8.0-1052.55~22.04.1

6.8.0-1052.55~22.04.1

ubuntu/linux-azure<5.15.0-1109.118

5.15.0-1109.118

ubuntu/linux-azure-5.19*

ubuntu/linux-azure-6.2*

ubuntu/linux-azure-6.5*

ubuntu/linux-azure-6.8<6.8.0-1059.65~22.04.1

6.8.0-1059.65~22.04.1

ubuntu/linux-azure-fde<5.15.0-1109.118.1

5.15.0-1109.118.1

ubuntu/linux-azure-fde-5.19*

ubuntu/linux-azure-fde-6.2*

ubuntu/linux-azure-fde-6.8<6.8.0-1058.65~22.04.1

6.8.0-1058.65~22.04.1

ubuntu/linux-gcp<5.15.0-1103.112

5.15.0-1103.112

ubuntu/linux-gcp-5.19*

ubuntu/linux-gcp-6.2*

ubuntu/linux-gcp-6.5*

ubuntu/linux-gcp-6.8<6.8.0-1054.57~22.04.1

6.8.0-1054.57~22.04.1

ubuntu/linux-gke<5.15.0-1099.105

5.15.0-1099.105

ubuntu/linux-gkeop<5.15.0-1086.94

5.15.0-1086.94

ubuntu/linux-hwe-5.19*

ubuntu/linux-hwe-6.2*

ubuntu/linux-hwe-6.5*

ubuntu/linux-hwe-6.8<6.8.0-110.110~22.04.1

6.8.0-110.110~22.04.1

ubuntu/linux-ibm<5.15.0-1097.100

5.15.0-1097.100

ubuntu/linux-ibm-6.8<6.8.0-1051.51~22.04.1

6.8.0-1051.51~22.04.1

ubuntu/linux-intel-iot-realtime*

ubuntu/linux-intel-iotg<5.15.0-1098.104

5.15.0-1098.104

ubuntu/linux-kvm<5.15.0-1095.100

5.15.0-1095.100

ubuntu/linux-lowlatency<5.15.0-173.183

5.15.0-173.183

ubuntu/linux-lowlatency-hwe-5.19*

ubuntu/linux-lowlatency-hwe-6.2*

ubuntu/linux-lowlatency-hwe-6.5*

ubuntu/linux-lowlatency-hwe-6.8<6.8.0-110.110.1~22.04.1

6.8.0-110.110.1~22.04.1

ubuntu/linux-nvidia<5.15.0-1098.99

5.15.0-1098.99

ubuntu/linux-nvidia-6.2*

ubuntu/linux-nvidia-6.5*

ubuntu/linux-nvidia-6.8<6.8.0-1051.54~22.04.1

6.8.0-1051.54~22.04.1

ubuntu/linux-nvidia-tegra<5.15.0-1055.55

5.15.0-1055.55

ubuntu/linux-nvidia-tegra-igx<5.15.0-1044.44

5.15.0-1044.44

ubuntu/linux-oem-5.17*

ubuntu/linux-oem-6.0*

ubuntu/linux-oem-6.1*

ubuntu/linux-oem-6.5*

ubuntu/linux-oracle<5.15.0-1100.106

5.15.0-1100.106

ubuntu/linux-oracle-6.5*

ubuntu/linux-oracle-6.8<6.8.0-1049.50~22.04.1

6.8.0-1049.50~22.04.1

ubuntu/linux-raspi<5.15.0-1097.100

5.15.0-1097.100

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-riscv-6.5*

ubuntu/linux-riscv-6.8<6.8.0-110.110~22.04.1

6.8.0-110.110~22.04.1

ubuntu/linux-starfive-5.19*

ubuntu/linux-starfive-6.2*

ubuntu/linux-starfive-6.5*

ubuntu/linux-xilinx-zynqmp<5.15.0-1067.71

5.15.0-1067.71

ubuntu/linux-bluefield<5.15.0-1086.88

5.15.0-1086.88

ubuntu/linux-intel-iot-realtime<5.15.0-1094.96

5.15.0-1094.96

ubuntu/linux-realtime<5.15.0-1102.111

5.15.0-1102.111

ubuntu/linux-realtime-6.8<6.8.1-1047.48~22.04.1

6.8.1-1047.48~22.04.1

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips<5.15.0-1103.110+fips1

5.15.0-1103.110+fips1

ubuntu/linux-azure-fips<5.15.0-1109.118+fips1

5.15.0-1109.118+fips1

ubuntu/linux-fips<5.15.0-173.183+fips1

5.15.0-173.183+fips1

ubuntu/linux-gcp-fips<5.15.0-1103.112+fips1

5.15.0-1103.112+fips1

ubuntu/linux<6.8.0-110.110

6.8.0-110.110

ubuntu/linux-aws<6.8.0-1052.55

6.8.0-1052.55

ubuntu/linux-aws-6.14*

ubuntu/linux-aws-6.17<6.17.0-1009.9~24.04.2

6.17.0-1009.9~24.04.2

ubuntu/linux-azure<6.8.0-1054.60

6.8.0-1054.60

ubuntu/linux-azure-6.11*

ubuntu/linux-azure-6.14*

ubuntu/linux-azure-6.17<6.17.0-1010.10~24.04.1

6.17.0-1010.10~24.04.1

ubuntu/linux-azure-fde<6.8.0-1058.65

6.8.0-1058.65

ubuntu/linux-azure-fde-6.14*

ubuntu/linux-azure-nvidia<6.8.0-1039.42

6.8.0-1039.42

ubuntu/linux-azure-nvidia-6.14*

ubuntu/linux-gcp<6.8.0-1054.57

6.8.0-1054.57

ubuntu/linux-gcp-6.11*

ubuntu/linux-gcp-6.14*

ubuntu/linux-gcp-6.17<6.17.0-1009.9~24.04.3

6.17.0-1009.9~24.04.3

ubuntu/linux-gke<6.8.0-1050.56

6.8.0-1050.56

ubuntu/linux-gkeop<6.8.0-1037.40

6.8.0-1037.40

ubuntu/linux-hwe-6.11*

ubuntu/linux-hwe-6.14*

ubuntu/linux-hwe-6.17<6.17.0-19.19~24.04.2

6.17.0-19.19~24.04.2

ubuntu/linux-ibm<6.8.0-1051.51

6.8.0-1051.51

ubuntu/linux-lowlatency<6.8.0-110.110.1

6.8.0-110.110.1

ubuntu/linux-lowlatency-hwe-6.11*

ubuntu/linux-nvidia<6.8.0-1051.54

6.8.0-1051.54

ubuntu/linux-nvidia-6.11*

ubuntu/linux-nvidia-6.17<6.17.0-1018.18

6.17.0-1018.18

ubuntu/linux-nvidia-lowlatency<6.8.0-1051.54.1

6.8.0-1051.54.1

ubuntu/linux-nvidia-tegra<6.8.0-1022.22

6.8.0-1022.22

ubuntu/linux-oem-6.11*

ubuntu/linux-oem-6.14*

ubuntu/linux-oem-6.17<6.17.0-1017.17

6.17.0-1017.17

ubuntu/linux-oem-6.8*

ubuntu/linux-oracle<6.8.0-1049.50

6.8.0-1049.50

ubuntu/linux-oracle-6.14*

ubuntu/linux-oracle-6.17<6.17.0-1009.9~24.04.1

6.17.0-1009.9~24.04.1

ubuntu/linux-raspi<6.8.0-1052.56

6.8.0-1052.56

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-6.14*

ubuntu/linux-riscv-6.17<6.17.0-19.19.1~24.04.1

6.17.0-19.19.1~24.04.1

ubuntu/linux-xilinx<6.8.0-1028.29

6.8.0-1028.29

ubuntu/linux-bluefield<6.8.0-1017.21

6.8.0-1017.21

ubuntu/linux-raspi-realtime<6.8.0-2042.43

6.8.0-2042.43

ubuntu/linux-realtime<6.8.1-1047.48

6.8.1-1047.48

ubuntu/linux-realtime-6.14*

ubuntu/linux-realtime-6.17<6.17.0-1008.9~24.04.1

6.17.0-1008.9~24.04.1

ubuntu/linux-aws-fips<6.8.0-1052.55+fips1

6.8.0-1052.55+fips1

ubuntu/linux-azure-fips<6.8.0-1053.59+fips1

6.8.0-1053.59+fips1

ubuntu/linux-fips<6.8.0-110.110+fips2

6.8.0-110.110+fips2

ubuntu/linux-gcp-fips<6.8.0-1054.57+fips1

6.8.0-1054.57+fips1

ubuntu/linux<6.17.0-19.19

6.17.0-19.19

ubuntu/linux-aws<6.17.0-1009.9

6.17.0-1009.9

ubuntu/linux-azure<6.17.0-1010.10

6.17.0-1010.10

ubuntu/linux-azure-fde*

ubuntu/linux-gcp<6.17.0-1009.9

6.17.0-1009.9

ubuntu/linux-oracle<6.17.0-1009.9

6.17.0-1009.9

ubuntu/linux-raspi<6.17.0-1010.10

6.17.0-1010.10

ubuntu/linux-realtime<6.17.0-1008.9

6.17.0-1008.9

ubuntu/linux-riscv<6.17.0-19.19.1

6.17.0-19.19.1

ubuntu/linux-vmware*

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 5.15.0-1103.110~20.04.1
Upgrade
Upgrade ubuntu/linux-azure-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1110.119~20.04.1
Upgrade
Upgrade ubuntu/linux-gcp-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1103.112~20.04.1
Upgrade
Upgrade ubuntu/linux-hwe-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-173.183~20.04.1
Upgrade
Upgrade ubuntu/linux-ibm-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1097.100~20.04.1
Upgrade
Upgrade ubuntu/linux-intel-iotg-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1098.104~20.04.1
Upgrade
Upgrade ubuntu/linux-lowlatency-hwe-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-173.183~20.04.1
Upgrade
Upgrade ubuntu/linux-nvidia-tegra-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1055.55~20.04.1
Upgrade
Upgrade ubuntu/linux-oracle-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1100.106~20.04.1
Upgrade
Upgrade ubuntu/linux-riscv-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1097.101~20.04.1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 5.15.0-173.183
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 5.15.0-1103.110
Upgrade
Upgrade ubuntu/linux-aws-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1052.55~22.04.1
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 5.15.0-1109.118
Upgrade
Upgrade ubuntu/linux-azure-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1059.65~22.04.1
Upgrade
Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 5.15.0-1109.118.1
Upgrade
Upgrade ubuntu/linux-azure-fde-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1058.65~22.04.1
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 5.15.0-1103.112
Upgrade
Upgrade ubuntu/linux-gcp-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1054.57~22.04.1
Upgrade
Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 5.15.0-1099.105
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Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.
Fixed in 5.15.0-1086.94
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Upgrade ubuntu/linux-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-110.110~22.04.1
Upgrade
Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 5.15.0-1097.100
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Upgrade ubuntu/linux-ibm-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1051.51~22.04.1
Upgrade
Upgrade ubuntu/linux-intel-iotg to a version that resolves this vulnerability.
Fixed in 5.15.0-1098.104
Upgrade
Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.
Fixed in 5.15.0-1095.100
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Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.
Fixed in 5.15.0-173.183
Upgrade
Upgrade ubuntu/linux-lowlatency-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-110.110.1~22.04.1
Upgrade
Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.
Fixed in 5.15.0-1098.99
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Upgrade ubuntu/linux-nvidia-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1051.54~22.04.1
Upgrade
Upgrade ubuntu/linux-nvidia-tegra to a version that resolves this vulnerability.
Fixed in 5.15.0-1055.55
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Upgrade ubuntu/linux-nvidia-tegra-igx to a version that resolves this vulnerability.
Fixed in 5.15.0-1044.44
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 5.15.0-1100.106
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Upgrade ubuntu/linux-oracle-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1049.50~22.04.1
Upgrade
Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.
Fixed in 5.15.0-1097.100
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Upgrade ubuntu/linux-riscv-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-110.110~22.04.1
Upgrade
Upgrade ubuntu/linux-xilinx-zynqmp to a version that resolves this vulnerability.
Fixed in 5.15.0-1067.71
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Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.
Fixed in 5.15.0-1086.88
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Upgrade ubuntu/linux-intel-iot-realtime to a version that resolves this vulnerability.
Fixed in 5.15.0-1094.96
Upgrade
Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 5.15.0-1102.111
Upgrade
Upgrade ubuntu/linux-realtime-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.1-1047.48~22.04.1
Upgrade
Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1103.110+fips1
Upgrade
Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1109.118+fips1
Upgrade
Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-173.183+fips1
Upgrade
Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1103.112+fips1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 6.8.0-110.110
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 6.8.0-1052.55
Upgrade
Upgrade ubuntu/linux-aws-6.17 to a version that resolves this vulnerability.
Fixed in 6.17.0-1009.9~24.04.2
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 6.8.0-1054.60
Upgrade
Upgrade ubuntu/linux-azure-6.17 to a version that resolves this vulnerability.
Fixed in 6.17.0-1010.10~24.04.1
Upgrade
Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 6.8.0-1058.65
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Upgrade ubuntu/linux-azure-nvidia to a version that resolves this vulnerability.
Fixed in 6.8.0-1039.42
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Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 6.8.0-1054.57
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Upgrade ubuntu/linux-gcp-6.17 to a version that resolves this vulnerability.
Fixed in 6.17.0-1009.9~24.04.3
Upgrade
Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 6.8.0-1050.56
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Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.
Fixed in 6.8.0-1037.40
Upgrade
Upgrade ubuntu/linux-hwe-6.17 to a version that resolves this vulnerability.
Fixed in 6.17.0-19.19~24.04.2
Upgrade
Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 6.8.0-1051.51
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Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.
Fixed in 6.8.0-110.110.1
Upgrade
Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.
Fixed in 6.8.0-1051.54
Upgrade
Upgrade ubuntu/linux-nvidia-6.17 to a version that resolves this vulnerability.
Fixed in 6.17.0-1018.18
Upgrade
Upgrade ubuntu/linux-nvidia-lowlatency to a version that resolves this vulnerability.
Fixed in 6.8.0-1051.54.1
Upgrade
Upgrade ubuntu/linux-nvidia-tegra to a version that resolves this vulnerability.
Fixed in 6.8.0-1022.22
Upgrade
Upgrade ubuntu/linux-oem-6.17 to a version that resolves this vulnerability.
Fixed in 6.17.0-1017.17
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 6.8.0-1049.50
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Fixed in 6.17.0-1009.9~24.04.1
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Fixed in 6.8.0-1052.56
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Fixed in 6.17.0-19.19.1~24.04.1
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Fixed in 6.8.0-1028.29
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Fixed in 6.8.0-1017.21
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Fixed in 6.8.0-2042.43
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Fixed in 6.8.1-1047.48
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Fixed in 6.17.0-1008.9~24.04.1
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Fixed in 6.8.0-1052.55+fips1
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Fixed in 6.8.0-1053.59+fips1
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Fixed in 6.8.0-110.110+fips2
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Fixed in 6.8.0-1054.57+fips1
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Fixed in 6.17.0-19.19
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Fixed in 6.17.0-1009.9
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Fixed in 6.17.0-1010.10
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Fixed in 6.17.0-1009.9
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Fixed in 6.17.0-1009.9
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Fixed in 6.17.0-1010.10
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Fixed in 6.17.0-1008.9
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Fixed in 6.17.0-19.19.1

Event History

Dec 24, 2025

CVE Published

via OSV·11:16 AM

Data Sourced

via OSV·11:16 AM

DescriptionSeverityAffected Software

Frequently Asked Questions

What sequence triggers the use-after-free condition?

The issue occurs when NBD_CMD_CONNECT races with NBD_CLEAR_SOCK during nbd_genl_connect. The reported sequence drops the configuration reference count to zero during close, after which nbd_genl_connect attempts to increment it.

How can I identify a system that has encountered this issue?

Look for a kernel warning stating "refcount_t: addition on 0; use-after-free" with nbd_genl_connect in the stack trace. The warning may also include calls through genl_family_rcv_msg_doit and genl_rcv_msg.

UBUNTU-CVE-2025-68366: Use After Free

Affected Software

Remediation

Event History

Frequently Asked Questions

What sequence triggers the use-after-free condition?

How can I identify a system that has encountered this issue?

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