Improper input validation in Linux kernel - CVE-2026-31637

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Main Vulnerability Database Vulnerabilities #VU127751

Improper input validation in Linux kernel - CVE-2026-31637

Published: April 25, 2026


Vulnerability identifier: #VU127751
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-31637
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper input validation in rxkad_decrypt_ticket() when processing a malformed RXKAD RESPONSE ticket with a non-block-aligned length. A remote attacker can send a specially crafted response ticket to cause a denial of service.


Affected software

Linux kernel
Debian Linux
Ubuntu
linux (Ubuntu package)
linux-lts-xenial (Ubuntu package)
linux-kvm (Ubuntu package)
linux-aws (Ubuntu package)
linux-fips (Ubuntu package)
linux-hwe (Ubuntu package)
linux-gcp (Ubuntu package)
linux-azure (Ubuntu package)
linux-oracle (Ubuntu package)
linux-aws-hwe (Ubuntu package)
linux-azure-4.15 (Ubuntu package)
linux-gcp-4.15 (Ubuntu package)
linux-gcp-fips (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-aws-fips (Ubuntu package)
linux-hwe-5.4 (Ubuntu package)
linux-ibm (Ubuntu package)
linux-bluefield (Ubuntu package)
linux-xilinx-zynqmp (Ubuntu package)
linux-iot (Ubuntu package)
linux-raspi (Ubuntu package)
linux-ibm-5.4 (Ubuntu package)
linux-aws-5.4 (Ubuntu package)
linux-azure-5.4 (Ubuntu package)
linux-oracle-5.4 (Ubuntu package)
linux-gcp-5.4 (Ubuntu package)
linux-raspi-5.4 (Ubuntu package)
linux-lowlatency (Ubuntu package)
linux-gke (Ubuntu package)
linux-aws-5.15 (Ubuntu package)
linux-lowlatency-hwe-5.15 (Ubuntu package)
linux-hwe-5.15 (Ubuntu package)
linux-azure-5.15 (Ubuntu package)
linux-ibm-5.15 (Ubuntu package)
linux-intel-iotg (Ubuntu package)
linux-gkeop (Ubuntu package)
linux-nvidia-tegra-igx (Ubuntu package)
linux-azure-fde-5.15 (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-realtime (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-intel-iotg-5.15 (Ubuntu package)
linux-oracle-5.15 (Ubuntu package)
linux-gcp-5.15 (Ubuntu package)
linux-nvidia-tegra-5.15 (Ubuntu package)
linux-intel-iot-realtime (Ubuntu package)
linux-hwe-6.17 (Ubuntu package)
linux-gcp-6.17 (Ubuntu package)
linux-azure-6.17 (Ubuntu package)
linux-oracle-6.17 (Ubuntu package)
linux-oem-6.17 (Ubuntu package)
linux-nvidia-6.17 (Ubuntu package)
linux-aws-6.17 (Ubuntu package)
linux-realtime-6.17 (Ubuntu package)
linux-hwe-6.8 (Ubuntu package)
linux-aws-6.8 (Ubuntu package)
linux-azure-fde-6.8 (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux-raspi-realtime (Ubuntu package)
linux (Debian package)
linux-azure-fde-6.17 (Ubuntu package)

How to mitigate CVE-2026-31637

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - addressed in versions 3.13.0-214.265, 4.4.0-283.317, 4.15.0-253.265, 5.4.0-233.253, 5.15.0-185.195, 6.8.0-134.134, 6.8.0-1057.58~22.04.1, 6.8.0-1058.61~22.04.1, 6.8.0-1058.61+fips1, 6.8.0-1060.61, 6.8.0-1060.63~22.04.1, 6.8.0-1060.63+fips1, 6.8.0-1063.69, 6.8.0-1063.69+fips1, 6.8.1-1055.56~22.04.1, 6.8.1-1055.56, 6.17.0-40.40
linux-lts-xenial (Ubuntu package) - update to 4.4.0-283.317~14.04.1
linux-kvm (Ubuntu package) - addressed in versions 4.4.0-1157.168, 4.15.0-1176.181, 5.4.0-1148.157, 5.15.0-1103.108
linux-aws (Ubuntu package) - addressed in versions 4.4.0-1156.162, 4.4.0-1194.209, 4.15.0-1194.207, 5.4.0-1161.172, 5.15.0-1111.118, 6.17.0-1019.19
linux-fips (Ubuntu package) - addressed in versions 4.4.0-1126.133, 4.15.0-1149.161, 5.4.0-1135.145, 5.15.0-185.195+fips1
linux-hwe (Ubuntu package) - update to 4.15.0-253.265~16.04.1
linux-gcp (Ubuntu package) - addressed in versions 4.15.0-1187.204~16.04.1, 5.4.0-1164.173, 5.15.0-1111.121, 6.17.0-1020.22
linux-azure (Ubuntu package) - addressed in versions 4.15.0-1204.219~16.04.1, 4.15.0-1205.220~14.04.1, 5.4.0-1166.172, 5.15.0-1116.125, 6.8.0-1063.71~22.04.1, 6.8.0-1063.71
linux-oracle (Ubuntu package) - addressed in versions 4.15.0-1156.167~16.04.1, 4.15.0-1156.167, 5.4.0-1159.169, 5.15.0-1108.114, 6.17.0-1018.18
linux-aws-hwe (Ubuntu package) - update to 4.15.0-1194.207~16.04.1
linux-azure-4.15 (Ubuntu package) - update to 4.15.0-1204.219
linux-gcp-4.15 (Ubuntu package) - update to 4.15.0-1187.204
linux-gcp-fips (Ubuntu package) - addressed in versions 4.15.0-2095.101, 5.4.0-1164.173+fips1, 5.15.0-1111.121+fips1
linux-azure-fips (Ubuntu package) - addressed in versions 4.15.0-2112.118, 5.4.0-1166.172+fips1, 5.15.0-1116.125+fips1, 6.8.0-134.134+fips1, 6.8.0-1062.69+fips1
linux-aws-fips (Ubuntu package) - addressed in versions 4.15.0-2132.138, 5.4.0-1161.172+fips1, 5.15.0-1111.118+fips1
linux-hwe-5.4 (Ubuntu package) - update to 5.4.0-233.253~18.04.1
linux-ibm (Ubuntu package) - addressed in versions 5.4.0-1107.112, 5.15.0-1105.109
linux-bluefield (Ubuntu package) - update to 5.4.0-1120.127
linux-xilinx-zynqmp (Ubuntu package) - addressed in versions 5.4.0-1079.83, 5.15.0-1074.78
linux-iot (Ubuntu package) - update to 5.4.0-1065.68
linux-raspi (Ubuntu package) - addressed in versions 5.4.0-1144.157, 5.15.0-1105.108, 6.8.0-1060.64, 6.17.0-1021.21
linux-ibm-5.4 (Ubuntu package) - update to 5.4.0-1107.112~18.04.1
linux-aws-5.4 (Ubuntu package) - update to 5.4.0-1161.172~18.04.1
linux-azure-5.4 (Ubuntu package) - update to 5.4.0-1166.172~18.04.1
linux-oracle-5.4 (Ubuntu package) - update to 5.4.0-1159.169~18.04.1
linux-gcp-5.4 (Ubuntu package) - update to 5.4.0-1164.173~18.04.1
linux-raspi-5.4 (Ubuntu package) - update to 5.4.0-1144.157~18.04.1
linux-lowlatency (Ubuntu package) - update to 5.15.0-183.193
linux-gke (Ubuntu package) - update to 5.15.0-1107.113
linux-aws-5.15 (Ubuntu package) - update to 5.15.0-1111.118~20.04.1
linux-lowlatency-hwe-5.15 (Ubuntu package) - update to 5.15.0-183.193~20.04.1
linux-hwe-5.15 (Ubuntu package) - update to 5.15.0-185.195~20.04.1
linux-azure-5.15 (Ubuntu package) - update to 5.15.0-1116.125~20.04.1
linux-ibm-5.15 (Ubuntu package) - update to 5.15.0-1105.109~20.04.1
linux-intel-iotg (Ubuntu package) - update to 5.15.0-1106.112
linux-gkeop (Ubuntu package) - update to 5.15.0-1094.102
linux-nvidia-tegra-igx (Ubuntu package) - update to 5.15.0-1052.52
linux-azure-fde-5.15 (Ubuntu package) - update to 5.15.0-1116.125~20.04.1
linux-nvidia-tegra (Ubuntu package) - addressed in versions 5.15.0-1063.63, 6.8.0-1029.30
linux-realtime (Ubuntu package) - addressed in versions 5.15.0-1110.119, 6.17.0-1017.19
linux-nvidia (Ubuntu package) - update to 5.15.0-1106.107
linux-intel-iotg-5.15 (Ubuntu package) - update to 5.15.0-1106.112~20.04.1
linux-oracle-5.15 (Ubuntu package) - update to 5.15.0-1108.114~20.04.1
linux-gcp-5.15 (Ubuntu package) - update to 5.15.0-1111.121~20.04.1
linux-nvidia-tegra-5.15 (Ubuntu package) - update to 5.15.0-1063.63~20.04.1
linux-intel-iot-realtime (Ubuntu package) - update to 5.15.0-1103.105
linux-hwe-6.17 (Ubuntu package) - update to 6.17.0-40.40~24.04.1
linux-gcp-6.17 (Ubuntu package) - update to 6.17.0-1020.22~24.04.1
linux-azure-6.17 (Ubuntu package) - update to 6.17.0-1021.21~24.04.1
linux-oracle-6.17 (Ubuntu package) - update to 6.17.0-1018.18~24.04.1
linux-oem-6.17 (Ubuntu package) - update to 6.17.0-1028.28
linux-nvidia-6.17 (Ubuntu package) - update to 6.17.0-1026.26
linux-aws-6.17 (Ubuntu package) - update to 6.17.0-1019.19~24.04.1
linux-realtime-6.17 (Ubuntu package) - update to 6.17.0-1017.19~24.04.1
linux-hwe-6.8 (Ubuntu package) - update to 6.8.0-136.136~22.04.1
linux-aws-6.8 (Ubuntu package) - addressed in versions 6.8.0-1045.48, 6.8.0-1057.58~22.04.1, 6.8.0-1058.61.1, 6.8.0-1058.64, 6.8.0-1060.61~22.04.1, 6.8.0-1060.63~22.04.1, 6.8.0-1063.69~22.04.1
linux-azure-fde-6.8 (Ubuntu package) - update to 6.8.0-1062.69~22.04.1
linux-azure-fde (Ubuntu package) - update to 6.8.0-1062.69
linux-raspi-realtime (Ubuntu package) - update to 6.8.0-2049.50
linux (Debian package) - update to 6.12.85-1
linux-azure-fde-6.17 (Ubuntu package) - update to 6.17.0-1018.18~24.04.1

External References

Related Security Bulletins