Out-of-bounds read in Linux kernel - CVE-2026-31712

CSH
CYBERSECURITY HELP
Sign In REGISTER
 
Main Vulnerability Database Vulnerabilities #VU128979

Out-of-bounds read in Linux kernel - CVE-2026-31712

Published: May 2, 2026


Vulnerability identifier: #VU128979
CSH Severity: Medium
CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-31712
CWE-ID: CWE-125
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

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

The vulnerability exists due to an out-of-bounds read in smb_check_perm_dacl() when processing a crafted DACL during SMB permission checks. A remote user can set a crafted ACL on a file they own and trigger a subsequent CREATE request to cause a denial of service.

The issue is reachable by an authenticated SMB client with permission to set an ACL on a file, and it is not pre-authentication. The out-of-bounds read is not reflected to the attacker, but KASAN reports and kernel state corruption are possible.


Affected software

Linux kernel
Ubuntu
openEuler
bpftool
kernel
python3-perf-debuginfo
python3-perf
perf-debuginfo
perf
kernel-tools-devel
kernel-tools-debuginfo
kernel-tools
kernel-source
kernel-headers
kernel-devel
kernel-debugsource
kernel-debuginfo
bpftool-debuginfo
linux (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-oracle-5.15 (Ubuntu package)
linux-gcp-5.15 (Ubuntu package)
linux-gcp (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux-hwe-6.8 (Ubuntu package)
linux-fips (Ubuntu package)
linux-ibm (Ubuntu package)
linux-oracle-6.8 (Ubuntu package)
linux-aws-6.8 (Ubuntu package)
linux-aws (Ubuntu package)
linux-raspi (Ubuntu package)
linux-azure-fde-6.8 (Ubuntu package)
linux-azure (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-gcp-fips (Ubuntu package)

How to mitigate CVE-2026-31712

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
bpftool - update to 5.10.0-317.0.0.220
kernel - update to 5.10.0-317.0.0.220
python3-perf-debuginfo - update to 5.10.0-317.0.0.220
python3-perf - update to 5.10.0-317.0.0.220
perf-debuginfo - update to 5.10.0-317.0.0.220
perf - update to 5.10.0-317.0.0.220
kernel-tools-devel - update to 5.10.0-317.0.0.220
kernel-tools-debuginfo - update to 5.10.0-317.0.0.220
kernel-tools - update to 5.10.0-317.0.0.220
kernel-source - update to 5.10.0-317.0.0.220
kernel-headers - update to 5.10.0-317.0.0.220
kernel-devel - update to 5.10.0-317.0.0.220
kernel-debugsource - update to 5.10.0-317.0.0.220
kernel-debuginfo - update to 5.10.0-317.0.0.220
bpftool-debuginfo - update to 5.10.0-317.0.0.220
linux (Ubuntu package) - addressed in versions 5.15.0-195.205~20.04.1, 5.15.0-195.205, 5.15.0-198.208~20.04.1, 5.15.0-198.208+fips1, 5.15.0-1080.84, 5.15.0-1100.108, 5.15.0-1109.111, 5.15.0-1109.114, 5.15.0-1111.115~20.04.1, 5.15.0-1111.115, 5.15.0-1112.118~20.04.1, 5.15.0-1112.118, 5.15.0-1113.119, 5.15.0-1114.120, 5.15.0-1116.125~20.04.1, 5.15.0-1117.124~20.04.1, 5.15.0-1117.124, 5.15.0-1117.124+fips1, 5.15.0-1122.131~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1123.132, 5.15.0-1123.132+fips1, 5.15.0.195.160, 5.15.0.195.205~20.04.1, 5.15.0.198.114, 5.15.0.198.171, 5.15.0.198.208~20.04.1, 5.15.0.1080.83~20.04.1, 5.15.0.1100.99, 5.15.0.1109.105, 5.15.0.1109.113, 5.15.0.1111.108, 5.15.0.1111.115~20.04.1, 5.15.0.1112.111, 5.15.0.1112.118~20.04.1, 5.15.0.1113.112, 5.15.0.1114.110, 5.15.0.1116.120, 5.15.0.1117.113, 5.15.0.1117.120, 5.15.0.1117.124~20.04.1, 5.15.0.1122.131~20.04.1, 5.15.0.1123.107, 5.15.0.1123.121, 5.15.0.1123.132~20.04.1, 6.8.0-136.136, 6.8.0-1046.50, 6.8.0-1059.67, 6.8.0-1064.72~22.04.1, 6.8.0-1064.72, 6.8.1-1056.57~22.04.2, 6.8.1-1056.57, 7.0.0-27.27
linux-nvidia (Ubuntu package) - addressed in versions 5.15.0-1112.113, 5.15.0.1112.112, 6.8.0-1059.62~22.04.1, 6.8.0-1059.62, 6.8.0-1059.62.1, 7.0.0-1013.13
linux-oracle-5.15 (Ubuntu package) - addressed in versions 5.15.0-1114.120~20.04.1, 5.15.0.1114.120~20.04.1
linux-gcp-5.15 (Ubuntu package) - addressed in versions 5.15.0-1118.128~20.04.1, 5.15.0.1118.128~20.04.1
linux-gcp (Ubuntu package) - addressed in versions 5.15.0-1118.128, 5.15.0-1118.128+fips1, 5.15.0.1118.107, 5.15.0.1118.115
linux-azure-fde (Ubuntu package) - addressed in versions 5.15.0-1122.131, 5.15.0.1122.131, 6.8.0-1062.69
linux-hwe-6.8 (Ubuntu package) - update to 6.8.0-136.136~22.04.1
linux-fips (Ubuntu package) - addressed in versions 6.8.0-136.136+fips2, 6.8.0-136.136.2~22.04.1, 6.8.0-136.136.2, 6.8.0-1058.61
linux-ibm (Ubuntu package) - addressed in versions 6.8.0-1030.31, 6.8.0-1033.34, 6.8.0-1061.62~22.04.1, 6.8.0-1061.62
linux-oracle-6.8 (Ubuntu package) - update to 6.8.0-1058.61~22.04.1
linux-aws-6.8 (Ubuntu package) - addressed in versions 6.8.0-1061.64~22.04.1, 6.8.0-1061.64+fips1
linux-aws (Ubuntu package) - update to 6.8.0-1061.64+1
linux-raspi (Ubuntu package) - addressed in versions 6.8.0-1061.65, 6.8.0-2050.52, 7.0.0-1014.14
linux-azure-fde-6.8 (Ubuntu package) - update to 6.8.0-1062.69~22.04.1
linux-azure (Ubuntu package) - addressed in versions 6.8.0-1063.71~22.04.1, 6.8.0-1063.71, 7.0.0-1009.9, 7.0.0-1010.10
linux-azure-fips (Ubuntu package) - update to 6.8.0-1063.71+fips2
linux-gcp-fips (Ubuntu package) - update to 6.8.0-1064.72+fips1

External References

Related Security Bulletins