SB20260406124 - Improper control of a resource through its lifetime in Linux kernel smb server
Published: April 6, 2026
Security Bulletin ID
SB20260406124
Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Improper control of a resource through its lifetime (CVE-ID: CVE-2026-31409)
The vulnerability allows a remote user to bypass session isolation.
The vulnerability exists due to improper state management in the ksmbd connection binding state when processing a multichannel SMB2_SESSION_SETUP request with SMB2_SESSION_REQ_FLAG_BINDING that fails. A remote user can send a failed binding request to bypass session isolation.
The issue occurs because subsequent ksmbd_session_lookup_all() calls fall back to the global sessions table after the connection remains in a binding state.
Remediation
Install update from vendor's website.
References
- https://git.kernel.org/stable/c/282343cf8a4a5a3603b1cb0e17a7083e4a593b03
- https://git.kernel.org/stable/c/6260fc85ed1298a71d24a75d01f8b2e56d489a60
- https://git.kernel.org/stable/c/6ebef4a220a1ebe345de899ebb9ae394206fe921
- https://git.kernel.org/stable/c/89afe5e2dbea6e9d8e5f11324149d06fa3a4efca
- https://git.kernel.org/stable/c/9feb2d1bf86d9e5e66b8565f37f8d3a7d281a772
- https://git.kernel.org/stable/c/d073870dab8f6dadced81d13d273ff0b21cb7f4e