CVE-2026-31402

A flaw was found in the Linux kernel's NFSv4.0 server (nfsd). A remote, unauthenticated attacker can exploit this heap overflow vulnerability in the NFSv4.0 LOCK replay cache. By using two cooperating NFSv4.0 clients, where one sets a lock with a large owner string and another requests a conflicting lock, the attacker can trigger a slab-out-of-bounds write. This corruption of adjacent heap memory could lead to arbitrary code execution or a denial of service.

This Important flaw in the Linux kernel's NFSv4.0 server (nfsd) allows a heap overflow. In this flaw a local attacker can trigger this by orchestrating two NFSv4.0 clients to create a conflicting lock with an oversized owner string.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.