CVE-2026-89637
A use‑after‑free bug in the Linux kernel’s CIFS client can be triggered by sending malformed SMB packets. The flaw can leak memory and allow attackers to corrupt memory, potentially leading to arbitrary code execution or a crash. The kernel has already been patched to fix the issue.
An official fix is available, so this entry is kept for 30 days and then removed automatically.
Who is affected
Linux systems that use the CIFS/SMB client in the kernel, such as servers and desktop distributions running SMB/CIFS file shares.
Real-world impact
An attacker could send specially crafted SMB packets to a vulnerable system, causing memory corruption that could lead to arbitrary code execution or a denial‑of‑service crash, thereby compromising the confidentiality, integrity, or availability of the affected machine.
Why this severity
The CVSS score of 9.8 reflects that the vulnerability can be exploited over the network with no authentication or user interaction, has low complexity, and can fully compromise confidentiality, integrity, and availability.
What to do about it
- 01Upgrade the Linux kernel to a version that includes the fix for CVE-2026-89637.
- 02Reboot the system to load the updated kernel.
NVD-referenced vendor advisory
Timeline
- Sep 11, 2026 · 2d agoPublishedDisclosed and added to the National Vulnerability Database.
- Sep 13, 2026 · 6h agoOfficial fix availableA vendor patch or mitigation now exists — see the remediation steps above.