SB20260502145 - Out-of-bounds read in Linux kernel smb client

Description

This security bulletin contains information about 1 vulnerability.

1) Out-of-bounds read (CVE-ID: CVE-2026-31709)

CWE-ID: CWE-125 - Out-of-bounds read

CVSSv4: 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/E:U/U:Green

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

The vulnerability exists due to an out-of-bounds read in cifsacl DACL rewrite helpers when processing a server-supplied truncated DACL. A remote attacker can send a malformed ACL response to cause a denial of service.

The issue occurs because the incoming DACL body and each ACE were not structurally validated before chmod/chown security descriptor rebuild paths walked the ACE list.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/0a8cf165566ba55a39fd0f4de172119dd646d39a
• https://git.kernel.org/stable/c/b78db9bddc84136f6a0bb49e8883cf200dfb87a8