CVE-2025-21731: nbd: don't allow reconnect after disconnect

Q: What is the severity of CVE-2025-21731?

CVE-2025-21731 is classified as a moderate severity vulnerability in the Linux kernel.

Q: How do I fix CVE-2025-21731?

To mitigate CVE-2025-21731, it is recommended to update to the latest version of the Linux kernel where the vulnerability has been patched.

Q: What components are affected by CVE-2025-21731?

CVE-2025-21731 primarily affects the nbd (Network Block Device) component of the Linux kernel.

Q: What type of vulnerability is CVE-2025-21731?

CVE-2025-21731 is a use-after-free (UAF) vulnerability that can lead to potential arbitrary code execution.

Q: Can CVE-2025-21731 be exploited remotely?

Yes, CVE-2025-21731 could potentially be exploited remotely if the affected nbd service is improperly configured.

Published Feb 27, 2025

Updated

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

nbd: don't allow reconnect after disconnect

Following process can cause nbdconfig UAF:

1) grab nbdconfig temporarily;

2) nbdgenldisconnect() flush all recvwork() and release the initial reference:

nbdgenldisconnect nbddisconnectandput nbddisconnect flushworkqueue(nbd->recvworkq) if (testandclearbit(NBDRTHASCONFIGREF, ...)) nbdconfigput -> due to step 1), reference is still not zero

3) nbdgenlreconfigure() queue recvwork() again;

nbdgenlreconfigure config = nbdgetconfigunlocked(nbd) if (!config) -> succeed if (!testbit(NBDRTBOUND, ...)) -> succeed nbdreconnectsocket queuework(nbd->recvworkq, &args->work)

4) step 1) release the reference;

5) Finially, recvwork() will trigger UAF:

recvwork nbdconfigput(nbd) -> nbdconfig is freed atomicdec(&config->recvthreads) -> UAF

Fix the problem by clearing NBDRTBOUND in nbdgenldisconnect(), so that nbdgenlreconfigure() will fail.

Affected Software

222 affected componentsFixes available

Linux Kernel

Microsoft cbl2 kernel 5.15.180.1-1

Patch available

Microsoft cbl2 kernel 5.15.176.3-3

Patch available

Microsoft cbl2 kernel 5.15.176.3-3

Patch available

Linux Linux kernel>=4.12<5.4.291

Linux Linux kernel>=5.5<5.10.235

Linux Linux kernel>=5.11<5.15.179

Linux Linux kernel>=5.16<6.1.129

Linux Linux kernel>=6.2<6.6.76

Linux Linux kernel>=6.7<6.12.13

Linux Linux kernel>=6.13<6.13.2

linux/kernel>=4.12.0<5.4.291

5.4.291

linux/kernel>=5.5.0<5.10.235

5.10.235

linux/kernel>=5.11.0<5.15.179

5.15.179

linux/kernel>=5.16.0<6.1.129

6.1.129

linux/kernel>=6.2.0<6.6.76

6.6.76

linux/kernel>=6.7.0<6.12.13

6.12.13

linux/kernel>=6.13.0<6.13.2

6.13.2

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<5.4.0-1146.156~18.04.1

5.4.0-1146.156~18.04.1

ubuntu/linux-azure*

ubuntu/linux-azure-4.15*

ubuntu/linux-azure-5.3*

ubuntu/linux-azure-5.4<5.4.0-1151.158~18.04.1

5.4.0-1151.158~18.04.1

ubuntu/linux-azure-edge*

ubuntu/linux-gcp*

ubuntu/linux-gcp-4.15*

ubuntu/linux-gcp-5.3*

ubuntu/linux-gcp-5.4<5.4.0-1149.158~18.04.1

5.4.0-1149.158~18.04.1

ubuntu/linux-gke-4.15*

ubuntu/linux-gke-5.4*

ubuntu/linux-gkeop-5.4*

ubuntu/linux-hwe*

ubuntu/linux-hwe-5.4<5.4.0-216.236~18.04.1

5.4.0-216.236~18.04.1

ubuntu/linux-hwe-edge*

ubuntu/linux-ibm-5.4<5.4.0-1092.97~18.04.1

5.4.0-1092.97~18.04.1

ubuntu/linux-kvm*

ubuntu/linux-oem*

ubuntu/linux-oracle*

ubuntu/linux-oracle-5.0*

ubuntu/linux-oracle-5.3*

ubuntu/linux-oracle-5.4<5.4.0-1144.154~18.04.1

5.4.0-1144.154~18.04.1

ubuntu/linux-raspi-5.4<5.4.0-1129.142~18.04.1

5.4.0-1129.142~18.04.1

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<5.4.0-216.236

5.4.0-216.236

ubuntu/linux-aws<5.4.0-1146.156

5.4.0-1146.156

ubuntu/linux-aws-5.15<5.15.0-1084.91~20.04.1

5.15.0-1084.91~20.04.1

ubuntu/linux-azure<5.4.0-1151.158

5.4.0-1151.158

ubuntu/linux-azure-5.15<5.15.0-1089.98~20.04.1

5.15.0-1089.98~20.04.1

ubuntu/linux-bluefield<5.4.0-1105.112

5.4.0-1105.112

ubuntu/linux-gcp<5.4.0-1149.158

5.4.0-1149.158

ubuntu/linux-gcp-5.15<5.15.0-1083.92~20.04.1

5.15.0-1083.92~20.04.1

ubuntu/linux-ibm<5.4.0-1092.97

5.4.0-1092.97

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-kvm<5.4.0-1133.142

5.4.0-1133.142

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<5.4.0-1144.154

5.4.0-1144.154

ubuntu/linux-oracle-5.15<5.15.0-1081.87~20.04.1

5.15.0-1081.87~20.04.1

ubuntu/linux-raspi<5.4.0-1129.142

5.4.0-1129.142

ubuntu/linux-riscv-5.15<5.15.0-1079.83~20.04.1

5.15.0-1079.83~20.04.1

ubuntu/linux-xilinx-zynqmp<5.4.0-1064.68

5.4.0-1064.68

ubuntu/linux-aws-5.11*

ubuntu/linux-aws-5.13*

ubuntu/linux-aws-5.8*

ubuntu/linux-azure-5.11*

ubuntu/linux-azure-5.13*

ubuntu/linux-azure-5.8*

ubuntu/linux-azure-fde*

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-intel-5.13*

ubuntu/linux-iot<5.4.0-1051.54

5.4.0-1051.54

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-5.11*

ubuntu/linux-oracle-5.13*

ubuntu/linux-oracle-5.8*

ubuntu/linux-raspi2*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.11*

ubuntu/linux-riscv-5.8*

ubuntu/linux-aws-fips<5.4.0-1146.156+fips1

5.4.0-1146.156+fips1

ubuntu/linux-azure-fips<5.4.0-1151.158+fips1

5.4.0-1151.158+fips1

ubuntu/linux-fips<5.4.0-1120.130

5.4.0-1120.130

ubuntu/linux-gcp-fips<5.4.0-1149.158+fips1

5.4.0-1149.158+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<6.8.0-1032.34~22.04.1

6.8.0-1032.34~22.04.1

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<6.8.0-1033.35~22.04.1

6.8.0-1033.35~22.04.1

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<6.8.0-64.67~22.04.1

6.8.0-64.67~22.04.1

ubuntu/linux-ibm<5.15.0-1076.79

5.15.0-1076.79

ubuntu/linux-ibm-6.8<6.8.0-1029.29~22.04.1

6.8.0-1029.29~22.04.1

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<6.8.0-64.67.1~22.04.1

6.8.0-64.67.1~22.04.1

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<6.8.0-1031.34~22.04.1

6.8.0-1031.34~22.04.1

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<6.8.0-1029.30~22.04.1

6.8.0-1029.30~22.04.1

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<6.8.0-64.67~22.04.1

6.8.0-64.67~22.04.1

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<6.8.1-1025.26~22.04.1

6.8.1-1025.26~22.04.1

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<6.8.0-64.67

6.8.0-64.67

ubuntu/linux-aws<6.8.0-1032.34

6.8.0-1032.34

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<6.8.0-1033.35

6.8.0-1033.35

ubuntu/linux-gcp-6.11<6.11.0-1015.15~24.04.1

6.11.0-1015.15~24.04.1

ubuntu/linux-gke<6.8.0-1028.32

6.8.0-1028.32

ubuntu/linux-gkeop<6.8.0-1015.17

6.8.0-1015.17

ubuntu/linux-hwe-6.11<6.11.0-26.26~24.04.1

6.11.0-26.26~24.04.1

ubuntu/linux-ibm<6.8.0-1029.29

6.8.0-1029.29

ubuntu/linux-lowlatency<6.8.0-64.67.1

6.8.0-64.67.1

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<6.8.0-1031.34

6.8.0-1031.34

ubuntu/linux-nvidia-6.11<6.11.0-1010.10

6.11.0-1010.10

ubuntu/linux-nvidia-lowlatency<6.8.0-1031.34.1

6.8.0-1031.34.1

ubuntu/linux-nvidia-tegra<6.8.0-1008.8

6.8.0-1008.8

ubuntu/linux-oem-6.11<6.11.0-1022.22

6.11.0-1022.22

ubuntu/linux-oem-6.8<6.8.0-1031.31

6.8.0-1031.31

ubuntu/linux-oracle<6.8.0-1029.30

6.8.0-1029.30

ubuntu/linux-raspi<6.8.0-1031.35

6.8.0-1031.35

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<6.8.0-2026.27

6.8.0-2026.27

ubuntu/linux-realtime<6.8.1-1025.26

6.8.1-1025.26

ubuntu/linux-fips<6.8.0-78.78+fips1

6.8.0-78.78+fips1

ubuntu/linux-vmware*

debian/linux<6.1.129-1

6.1.129-1

debian/linux<6.12.13-1

6.12.13-1

debian/linux<6.12.13-1

6.12.13-1

debian/linux

6.1.176-16.1.190-16.12.107-16.12.116-17.2.15-17.3.4-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 5.4.291
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Fixed in 5.10.235
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Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 5.15.179
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Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 6.1.129
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Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 6.6.76
Upgrade
Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 6.12.13
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Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 6.13.2
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Upgrade ubuntu/linux-aws-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1146.156~18.04.1
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Upgrade ubuntu/linux-azure-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1151.158~18.04.1
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Upgrade ubuntu/linux-gcp-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1149.158~18.04.1
Upgrade
Upgrade ubuntu/linux-hwe-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-216.236~18.04.1
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Upgrade ubuntu/linux-ibm-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1092.97~18.04.1
Upgrade
Upgrade ubuntu/linux-oracle-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1144.154~18.04.1
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Upgrade ubuntu/linux-raspi-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1129.142~18.04.1
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Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 5.4.0-216.236
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 5.4.0-1146.156
Upgrade
Upgrade ubuntu/linux-aws-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1084.91~20.04.1
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 5.4.0-1151.158
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Upgrade ubuntu/linux-azure-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1089.98~20.04.1
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Fixed in 5.4.0-1105.112
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Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 5.4.0-1149.158
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Upgrade ubuntu/linux-gcp-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1083.92~20.04.1
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Fixed in 5.4.0-1092.97
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Upgrade ubuntu/linux-ibm-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1076.79~20.04.1
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Fixed in 5.15.0-1079.85~20.04.1
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Fixed in 5.4.0-1133.142
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Upgrade ubuntu/linux-lowlatency-hwe-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-140.150~20.04.1
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Fixed in 5.4.0-1144.154
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Fixed in 5.15.0-1081.87~20.04.1
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Fixed in 5.4.0-1129.142
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Upgrade ubuntu/linux-riscv-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1079.83~20.04.1
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Fixed in 5.4.0-1064.68
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Upgrade ubuntu/linux-hwe-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-142.152~20.04.1
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Fixed in 5.4.0-1051.54
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Fixed in 5.15.0-1039.39~20.04.1
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Fixed in 5.4.0-1146.156+fips1
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Fixed in 5.4.0-1151.158+fips1
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Fixed in 5.4.0-1120.130
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Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.
Fixed in 5.4.0-1149.158+fips1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 5.15.0-140.150
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Fixed in 5.15.0-1084.91
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Upgrade ubuntu/linux-aws-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1032.34~22.04.1
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 5.15.0-1089.98
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Upgrade ubuntu/linux-azure-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1034.39~22.04.1
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Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 5.15.0-1089.98.1
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Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 5.15.0-1083.92
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Upgrade ubuntu/linux-gcp-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1033.35~22.04.1
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Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 5.15.0-1081.87
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Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.
Fixed in 5.15.0-1066.74
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Upgrade ubuntu/linux-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-64.67~22.04.1
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Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 5.15.0-1076.79
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Upgrade ubuntu/linux-ibm-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1029.29~22.04.1
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Upgrade ubuntu/linux-intel-iotg to a version that resolves this vulnerability.
Fixed in 5.15.0-1079.85
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Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.
Fixed in 5.15.0-1080.85
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Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.
Fixed in 5.15.0-140.150
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Upgrade ubuntu/linux-lowlatency-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-64.67.1~22.04.1
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Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.
Fixed in 5.15.0-1078.79
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Upgrade ubuntu/linux-nvidia-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1031.34~22.04.1
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Fixed in 5.15.0-1037.37
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Upgrade ubuntu/linux-nvidia-tegra-igx to a version that resolves this vulnerability.
Fixed in 5.15.0-1026.26
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Fixed in 5.15.0-1081.87
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Fixed in 6.8.0-1029.30~22.04.1
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Fixed in 5.15.0-1078.81
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Fixed in 6.8.0-64.67~22.04.1
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Fixed in 5.15.0-1050.54
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Fixed in 5.15.0-1066.68
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Fixed in 5.15.0-1077.79
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Fixed in 5.15.0-1084.93
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Fixed in 6.8.1-1025.26~22.04.1
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Fixed in 5.15.0-1084.91+fips1
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Fixed in 5.15.0-1089.98+fips1
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Fixed in 5.15.0-140.150+fips1
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Fixed in 5.15.0-1083.92+fips1
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Fixed in 6.8.0-64.67
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Fixed in 6.8.0-1032.34
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Fixed in 6.8.0-1034.39
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Fixed in 6.11.0-1015.15~24.04.1
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Fixed in 6.8.0-1022.23
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Fixed in 6.8.0-1033.35
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Fixed in 6.11.0-1015.15~24.04.1
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Fixed in 6.8.0-1028.32
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Fixed in 6.8.0-1015.17
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Fixed in 6.11.0-26.26~24.04.1
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Fixed in 6.8.0-1029.29
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Fixed in 6.8.0-64.67.1
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Fixed in 6.11.0-1014.15~24.04.1
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Fixed in 6.8.0-1031.34
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Fixed in 6.11.0-1010.10
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Fixed in 6.8.0-1031.34.1
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Fixed in 6.8.0-1008.8
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Fixed in 6.11.0-1022.22
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Fixed in 6.8.0-1031.31
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Fixed in 6.8.0-1029.30
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Fixed in 6.8.0-1031.35
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Fixed in 6.8.0-1017.18
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Fixed in 6.8.0-2026.27
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Fixed in 6.8.1-1025.26
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Fixed in 6.8.0-78.78+fips1
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Fixed in 6.1.129-1
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Fixed in 6.12.13-1
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Fixed in 6.1.176-1Fixed in 6.1.190-1Fixed in 6.12.107-1Fixed in 6.12.116-1Fixed in 7.2.15-1Fixed in 7.3.4-1
Configuration
Clear NBD_RT_BOUND in nbd_genl_disconnect() so that nbd_genl_reconfigure() fails after disconnect and cannot queue recv_work().
Linux kernel NBD NBD_RT_BOUND = cleared

Event History

Feb 27, 2025

CVE Published

via MITRE·02:07 AM

Data Sourced

via MITRE·02:07 AM

Description

Data Sourced

via OSV·02:07 AM

DescriptionSeverityAffected Software

Data Sourced

via NVD·02:15 AM

RemedyDescriptionSeverityWeaknessAffected Software

May 5, 2025

Data Sourced

via Microsoft·07:00 AM

DescriptionSeverityWeakness

Data Sourced

via Microsoft·07:00 AM

Affected Software

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

What is the severity of CVE-2025-21731?

CVE-2025-21731 is classified as a moderate severity vulnerability in the Linux kernel.

How do I fix CVE-2025-21731?

To mitigate CVE-2025-21731, it is recommended to update to the latest version of the Linux kernel where the vulnerability has been patched.

What components are affected by CVE-2025-21731?

CVE-2025-21731 primarily affects the nbd (Network Block Device) component of the Linux kernel.

What type of vulnerability is CVE-2025-21731?

CVE-2025-21731 is a use-after-free (UAF) vulnerability that can lead to potential arbitrary code execution.

Can CVE-2025-21731 be exploited remotely?

Yes, CVE-2025-21731 could potentially be exploited remotely if the affected nbd service is improperly configured.

CVE-2025-21731: nbd: don't allow reconnect after disconnect

Affected Software

Remediation

Event History

Peer vulnerabilities

Frequently Asked Questions

What is the severity of CVE-2025-21731?

How do I fix CVE-2025-21731?

What components are affected by CVE-2025-21731?

What type of vulnerability is CVE-2025-21731?

Can CVE-2025-21731 be exploited remotely?

Company

Resources

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