SB20260912155 - Out-of-bounds read in Linux kernel smb client
Published: September 12, 2026
Security Bulletin ID
SB20260912155
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Information disclosure
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Out-of-bounds read (CVE-ID: CVE-2026-89631)
CWE-ID: CWE-125 - Out-of-bounds read
CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to an out-of-bounds read in the CIFSTCon() SMB client tree connect response parser when processing a tree connect response with a byte count smaller than two. A remote attacker can send a malformed tree connect response to disclose sensitive information.
Disclosed bytes are exposed through /proc/fs/cifs/DebugData.
Remediation
Install update from vendor's website.