#VU124880 Heap-based buffer overflow in Linux kernel - CVE-2026-31402
Published: April 6, 2026
Vulnerability identifier: #VU124880
Vulnerability risk: Medium
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-31402
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
Linux kernel
Linux kernel
Software vendor:
Linux Foundation
Linux Foundation
Description
The vulnerability allows a remote attacker to corrupt heap memory.
The vulnerability exists due to a heap-based buffer overflow in the NFSv4.0 LOCK replay cache when encoding denied LOCK operation responses. A remote attacker can trigger conflicting lock requests with a large lock owner value to corrupt heap memory.
The issue is caused by copying an encoded LOCK denied response into a fixed 112-byte inline replay buffer without sufficient bounds checking, resulting in a slab out-of-bounds write of up to 944 bytes. Exploitation requires two cooperating NFSv4.0 clients and can be performed remotely without authentication.
Remediation
Install security update from vendor's repository.
External links
- https://git.kernel.org/stable/c/0f0e2a54a31a7f9ad2915db99156114872317388
- https://git.kernel.org/stable/c/5133b61aaf437e5f25b1b396b14242a6bb0508e2
- https://git.kernel.org/stable/c/8afb437ea1f70cacb4bbdf11771fb5c4d720b965
- https://git.kernel.org/stable/c/ae8498337dfdfda71bdd0b807c9a23a126011d76
- https://git.kernel.org/stable/c/c9452c0797c95cf2378170df96cf4f4b3bca7eff
- https://git.kernel.org/stable/c/dad0c3c0a8e5d1d6eb0fc455694ce3e25e6c57d0