Improper Initialization in Linux kernel - CVE-2026-53398
Published: July 21, 2026
Vulnerability identifier: #VU138876
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-53398
CWE-ID: CWE-665
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to improper initialization in nfsd4_decode_secinfo_no_name() when processing a truncated XDR stream for the SECINFO_NO_NAME operation. A remote attacker can send a specially crafted request to cause a denial of service.
The issue occurs because stale union contents from a previous operation can leave sin_exp non-NULL, leading the error cleanup path to call exp_put() on an invalid value.
Affected software
Linux kernel
How to mitigate CVE-2026-53398
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3
External References
- https://git.kernel.org/stable/c/161d1aaeb04d620d3692639700512bb5038c1e10
- https://git.kernel.org/stable/c/1e04be34cafae119e82bcaccd6d28a20f72a3647
- https://git.kernel.org/stable/c/46eb17d45be69d28c7a23ea03283b207426a8232
- https://git.kernel.org/stable/c/49de5d31dd8fdebf78bdeaf196b0ca5cd5c75439
- https://git.kernel.org/stable/c/5ec37edcb534f3fc92304be236d37f08e6545585
- https://git.kernel.org/stable/c/8836405abdc53ca3dd5fc68b2cf6f8f012fad011
- https://git.kernel.org/stable/c/9e18e83b8846a5c3fe13fc8a464b4865d33996c6
- https://git.kernel.org/stable/c/c8a24effd96d4779e2ad779654682304491c55a5