CVE-2025-21726: padata: avoid UAF for reorder_work

Q: What is the severity of CVE-2025-21726?

CVE-2025-21726 has a medium severity rating due to its potential to cause a use-after-free condition in the Linux kernel.

Q: How do I fix CVE-2025-21726?

To fix CVE-2025-21726, ensure that you update to the latest version of the Linux kernel that includes the relevant patches.

Q: What systems are affected by CVE-2025-21726?

CVE-2025-21726 affects all versions of the Linux kernel prior to the patched releases.

Q: What type of vulnerability is CVE-2025-21726?

CVE-2025-21726 is a use-after-free vulnerability in the padata subsystem of the Linux kernel.

Q: What could happen if CVE-2025-21726 is exploited?

Exploitation of CVE-2025-21726 could potentially lead to arbitrary code execution or a system crash.

Published Feb 27, 2025

Updated

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

padata: avoid UAF for reorderwork

Although the previous patch can avoid ps and ps UAF for doserial, it can not avoid potential UAF issue for reorderwork. This issue can happen just as below:

cryptorequest cryptorequest cryptodelalg padatadoserial ... padatareorder // processes all remaining // requests then breaks while (1) { if (!padata) break; ... }

padatadoserial // new request added listadd // sees the new request queuework(reorderwork) padatareorder queueworkon(squeue->work) ...

<kworker context> padataserialworker // completes new request, // no more outstanding // requests

cryptodelalg // free pd

<kworker context> invokepadatareorder // UAF of pd

To avoid UAF for 'reorderwork', get 'pd' ref before put 'reorderwork' into the 'serialwq' and put 'pd' ref until the 'serialwq' finish.

Other sources

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

padata: avoid UAF for reorderwork

Although the previous patch can avoid ps and ps UAF for doserial, it can not avoid potential UAF issue for reorderwork. This issue can happen just as below:

cryptorequest cryptorequest cryptodelalg padatadoserial ... padatareorder // processes all remaining // requests then breaks while (1) { if (!padata) break; ... }

padatadoserial // new request added listadd // sees the new request queuework(reorderwork) padatareorder queueworkon(squeue-work) ...

kworker context padataserialworker // completes new request, // no more outstanding // requests

cryptodelalg // free pd

kworker context invokepadatareorder // UAF of pd

To avoid UAF for 'reorderwork', get 'pd' ref before put 'reorderwork' into the 'serialwq' and put 'pd' ref until the 'serialwq' finish.

— IBM

Affected Software

192 affected componentsFixes available

Linux 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

Linux Linux kernel>=5.4.19<5.5

Linux Linux kernel>=5.5.3<5.10.235

Linux Linux kernel>=5.11<5.15.79

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

ubuntu/linux-hwe-edge*

ubuntu/linux-aws-5.0*

ubuntu/linux-aws-5.3*

ubuntu/linux-aws-5.4<5.4.0-1154.164~18.04.1

5.4.0-1154.164~18.04.1

ubuntu/linux-azure*

ubuntu/linux-azure-5.3*

ubuntu/linux-azure-5.4<5.4.0-1157.164~18.04.1

5.4.0-1157.164~18.04.1

ubuntu/linux-azure-edge*

ubuntu/linux-gcp*

ubuntu/linux-gcp-5.3*

ubuntu/linux-gcp-5.4<5.4.0-1157.166~18.04.1

5.4.0-1157.166~18.04.1

ubuntu/linux-gke-4.15*

ubuntu/linux-gke-5.4*

ubuntu/linux-gkeop-5.4*

ubuntu/linux-hwe*

ubuntu/linux-hwe-5.4<5.4.0-225.245~18.04.1

5.4.0-225.245~18.04.1

ubuntu/linux-hwe-edge*

ubuntu/linux-ibm-5.4<5.4.0-1100.105~18.04.1

5.4.0-1100.105~18.04.1

ubuntu/linux-oem*

ubuntu/linux-oracle-5.0*

ubuntu/linux-oracle-5.3*

ubuntu/linux-oracle-5.4<5.4.0-1152.162~18.04.1

5.4.0-1152.162~18.04.1

ubuntu/linux-raspi-5.4<5.4.0-1137.150~18.04.1

5.4.0-1137.150~18.04.1

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<5.4.0-225.245

5.4.0-225.245

ubuntu/linux-aws<5.4.0-1154.164

5.4.0-1154.164

ubuntu/linux-aws-5.11*

ubuntu/linux-aws-5.13*

ubuntu/linux-aws-5.8*

ubuntu/linux-azure<5.4.0-1157.164

5.4.0-1157.164

ubuntu/linux-azure-5.11*

ubuntu/linux-azure-5.13*

ubuntu/linux-azure-5.8*

ubuntu/linux-azure-fde*

ubuntu/linux-bluefield<5.4.0-1116.123

5.4.0-1116.123

ubuntu/linux-gcp<5.4.0-1157.166

5.4.0-1157.166

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<5.4.0-1100.105

5.4.0-1100.105

ubuntu/linux-intel-5.13*

ubuntu/linux-iot<5.4.0-1058.61

5.4.0-1058.61

ubuntu/linux-kvm<5.4.0-1141.150

5.4.0-1141.150

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<5.4.0-1152.162

5.4.0-1152.162

ubuntu/linux-oracle-5.11*

ubuntu/linux-oracle-5.13*

ubuntu/linux-oracle-5.8*

ubuntu/linux-raspi<5.4.0-1137.150

5.4.0-1137.150

ubuntu/linux-raspi2*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.11*

ubuntu/linux-riscv-5.8*

ubuntu/linux-xilinx-zynqmp<5.4.0-1072.76

5.4.0-1072.76

ubuntu/linux-aws-fips<5.4.0-1154.164+fips1

5.4.0-1154.164+fips1

ubuntu/linux-azure-fips<5.4.0-1158.165+fips1

5.4.0-1158.165+fips1

ubuntu/linux-fips<5.4.0-1128.138

5.4.0-1128.138

ubuntu/linux-gcp-fips<5.4.0-1157.166+fips1

5.4.0-1157.166+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*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

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Fixed in 5.4.0-1154.164~18.04.1
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Fixed in 5.4.0-1152.162~18.04.1
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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 5.15.0-140.150~20.04.1
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Fixed in 5.15.0-1081.87~20.04.1
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Fixed in 5.15.0-1079.83~20.04.1
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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 5.15.0-1084.93
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Fixed in 6.8.1-1025.26~22.04.1
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Fixed in 5.15.0-140.150+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
Compensating control
For padata reorder_work, acquire a reference to 'pd' before queueing reorder_work on 'serial_wq', and hold the 'pd' reference until the serial workqueue finishes to prevent a use-after-free.

Event History

Feb 27, 2025

CVE Published

via MITRE·02:07 AM

Data Sourced

via MITRE·02:07 AM

DescriptionSeverity

Data Sourced

via OSV·02:15 AM

DescriptionSeverityAffected Software

Data Sourced

via NVD·02:15 AM

RemedyDescriptionSeverityWeaknessAffected Software

Data Sourced

via Red Hat·03:04 AM

DescriptionSeverityAffected Software

Jul 8, 2026

Data Sourced

via IBM·12:00 AM

DescriptionAffected Software

Parent advisories

This vulnerability appears in the following advisories.

IBM-7279510

Frequently Asked Questions

What is the severity of CVE-2025-21726?

CVE-2025-21726 has a medium severity rating due to its potential to cause a use-after-free condition in the Linux kernel.

How do I fix CVE-2025-21726?

To fix CVE-2025-21726, ensure that you update to the latest version of the Linux kernel that includes the relevant patches.

What systems are affected by CVE-2025-21726?

CVE-2025-21726 affects all versions of the Linux kernel prior to the patched releases.

What type of vulnerability is CVE-2025-21726?

CVE-2025-21726 is a use-after-free vulnerability in the padata subsystem of the Linux kernel.

What could happen if CVE-2025-21726 is exploited?

Exploitation of CVE-2025-21726 could potentially lead to arbitrary code execution or a system crash.

CVE-2025-21726: padata: avoid UAF for reorder_work

Other sources

Affected Software

Remediation

Event History

Parent advisories

Frequently Asked Questions

What is the severity of CVE-2025-21726?

How do I fix CVE-2025-21726?

What systems are affected by CVE-2025-21726?

What type of vulnerability is CVE-2025-21726?

What could happen if CVE-2025-21726 is exploited?

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