NULL pointer dereference in Linux kernel - CVE-2026-90039
Published: September 16, 2026
Vulnerability identifier: #VU150241
CSH Severity: Low
CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-90039
CWE-ID: CWE-476
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local privileged user to cause a denial of service.
The vulnerability exists due to a null pointer dereference in NFSD NFSv4 state-revocation and asynchronous COPY walkers when processing unlock filesystem or export operations before NFSD startup completes. A local privileged user can write to the unlock filesystem interface or send an NFSD unlock netlink command to cause a denial of service.
The condition occurs when an NFSD listener has been created but no NFSD thread has started.
Affected software
Linux kernel
How to mitigate CVE-2026-90039
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3