CVE-2026-89630
A critical flaw in the Linux kernel’s SMB client handling could allow an attacker to crash the client or potentially take control of the system. The issue stems from an incorrect data‑offset check in the CIFS SMB protocol implementation. The flaw has been fixed in recent kernel commits.
An official fix is available, so this entry is kept for 30 days and then removed automatically.
Who is affected
Linux kernel, SMB client (CIFS) in any distribution that uses the affected kernel version.
Real-world impact
An attacker could crash the SMB client, causing a denial of service, and potentially gain control of the system.
Why this severity
The CVSS score of 9.1 reflects that the vulnerability can be exploited remotely without authentication, and it can completely compromise confidentiality and availability.
What to do about it
- 01Upgrade to a Linux kernel version that includes the fix (commits 83bfbd0bb902 and 097f5863b1a0).
NVD description indicates the vulnerability has been resolved in the Linux kernel.
Timeline
- Sep 11, 2026 · 2d agoPublishedDisclosed and added to the National Vulnerability Database.
- Sep 13, 2026 · 7h agoOfficial fix availableA vendor patch or mitigation now exists — see the remediation steps above.