CVE-2026-89551
A critical flaw in the Linux kernel's RPC subsystem can cause an integer underflow when trimming data from an XDR buffer, potentially leading to memory corruption and arbitrary code execution. The issue has been fixed by clamping the buffer length decrement to avoid underflow. The vulnerability is now resolved in the kernel.
An official fix is available, so this entry is kept for 30 days and then removed automatically.
Who is affected
Linux kernel, all versions before the patch that includes the fix.
Real-world impact
An attacker could exploit the underflow to corrupt memory, enabling arbitrary code execution or denial of service.
Why this severity
The CVSS score of 9.8 reflects that the flaw can be exploited remotely without authentication or user interaction, and it compromises confidentiality, integrity, and availability.
What to do about it
- 01Upgrade your Linux kernel to a version that includes the fix.
- 02Restart the system to load the updated kernel.
NVD description
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.