SB2026040647 - Improper access control in Linux kernel smb client

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Main Vulnerability Database SB2026040647

SB2026040647 - Improper access control in Linux kernel smb client

Published: April 6, 2026

Security Bulletin ID SB2026040647
Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Information disclosure

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 security vulnerability.


1) Improper access control (CVE-ID: CVE-2026-31392)

The vulnerability allows a local user to gain access to a share using incorrect credentials.

The vulnerability exists due to improper access control in the smb client session matching logic when processing cifs mounts with sec=krb5 and a username mount option. A local user can mount another share with a different username option to gain access to a share using incorrect credentials.

The issue occurs when Kerberos mounts reuse an SMB session from a previous mount even though a different username was specified, which can cause a mount that should fail with -ENOKEY to proceed with the first user's session.


Remediation

Install update from vendor's website.

References