CVE-2009-3623: Linux Kernel

High severity, CVSS 7.8. EPSS: 3.5% chance of exploitation in the next 30 days.

The lookup_cb_cred function in fs/nfsd/nfs4callback.c in the nfsd4 subsystem in the Linux kernel before 2.6.31.2 attempts to access a credentials cache even when a client specifies the AUTH_NULL authentication flavor, which allows remote attackers to cause a denial of service (NULL pointer dereference and system crash) via an NFSv4 mount request.

Affected products

• Linux Linux Kernel: up to and including 2.6.31.1; version 2.6.0 only; version 2.6.1 only; version 2.6.2 only; version 2.6.3 only; version 2.6.4 only; …

Published 2009-10-30. Last modified 2026-06-16.