Out-of-bounds write in Linux kernel - CVE-2026-31705

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Main Vulnerability Database Vulnerabilities #VU128990

Out-of-bounds write in Linux kernel - CVE-2026-31705

Published: May 2, 2026


Vulnerability identifier: #VU128990
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-2026-31705
CWE-ID: CWE-787
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 write in smb2_get_ea() when processing crafted QUERY_INFO compound requests. A remote user can send a specially crafted request to cause a denial of service.

The issue occurs when EA alignment padding is applied after an EA value exactly fills the remaining response buffer, causing 1 to 3 bytes to be written past the boundary into adjacent kernel heap memory.


Affected software

Linux kernel
Ubuntu
Anolis OS
python3-perf
kernel
bpftool
kernel-debug
kernel-debug-devel
kernel-devel
kernel-headers
kernel-tools
kernel-tools-libs
kernel-tools-libs-devel
perf
linux (Ubuntu package)
linux-fips (Ubuntu package)
linux-hwe-6.8 (Ubuntu package)
linux-ibm (Ubuntu package)
linux-oracle-6.8 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-aws-6.8 (Ubuntu package)
linux-aws (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux-azure-fde-6.8 (Ubuntu package)
linux-azure (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-gcp-fips (Ubuntu package)
linux-raspi (Ubuntu package)

How to mitigate CVE-2026-31705

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
python3-perf - update to 6.6.102-6
kernel - update to 6.6.102-6
bpftool - update to 6.6.102-6
kernel-debug - update to 6.6.102-6
kernel-debug-devel - update to 6.6.102-6
kernel-devel - update to 6.6.102-6
kernel-headers - update to 6.6.102-6
kernel-tools - update to 6.6.102-6
kernel-tools-libs - update to 6.6.102-6
kernel-tools-libs-devel - update to 6.6.102-6
perf - update to 6.6.102-6
linux (Ubuntu package) - addressed in versions 6.8.0-136.136, 6.8.0-1046.50, 6.8.0-1059.67, 6.8.0-1064.72, 6.8.0-1064.72~22.04.1, 6.8.1-1056.57, 6.8.1-1056.57~22.04.2, 7.0.0-27.27
linux-fips (Ubuntu package) - addressed in versions 6.8.0-136.136+fips2, 6.8.0-136.136.2, 6.8.0-136.136.2~22.04.1, 6.8.0-1058.61
linux-hwe-6.8 (Ubuntu package) - update to 6.8.0-136.136~22.04.1
linux-ibm (Ubuntu package) - addressed in versions 6.8.0-1030.31, 6.8.0-1033.34, 6.8.0-1061.62, 6.8.0-1061.62~22.04.1
linux-oracle-6.8 (Ubuntu package) - update to 6.8.0-1058.61~22.04.1
linux-nvidia (Ubuntu package) - addressed in versions 6.8.0-1059.62, 6.8.0-1059.62.1, 6.8.0-1059.62~22.04.1, 7.0.0-1013.13
linux-aws-6.8 (Ubuntu package) - addressed in versions 6.8.0-1061.64+fips1, 6.8.0-1061.64~22.04.1
linux-aws (Ubuntu package) - update to 6.8.0-1061.64+1
linux-azure-fde (Ubuntu package) - update to 6.8.0-1062.69
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, 6.8.0-1063.71~22.04.1, 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
linux-raspi (Ubuntu package) - update to 7.0.0-1014.14

External References

Related Security Bulletins