Improper access control in Linux kernel - CVE-2026-31503
Published: April 24, 2026
Vulnerability identifier: #VU127649
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-31503
CWE-ID: CWE-284
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to improper access control in the UDP socket bind conflict check when binding a wildcard address after multiple sockets are already bound to the same local port. A local user can bind sockets to multiple specific local addresses on the same port and then bind a wildcard address to bypass conflict detection and cause a denial of service.
The issue affects IPv6 wildcard, IPv4 wildcard, and IPv4-mapped wildcard addresses when the bind bucket count exceeds 10.
How to mitigate CVE-2026-31503
Install security update from vendor's repository.
Sources
- https://git.kernel.org/stable/c/0a360f7f73a06ac88f18917055fbcc79694252d7
- https://git.kernel.org/stable/c/18d84c45def3671d5c89fbdd5d4ab8a3217fe4b4
- https://git.kernel.org/stable/c/2297e38114316b26ae02f2d205c49b5511c5ed55
- https://git.kernel.org/stable/c/d6ace0dbcbb7fd285738bb87b42b71b01858c952
- https://git.kernel.org/stable/c/e537dd15d0d4ad989d56a1021290f0c674dd8b28
- https://git.kernel.org/stable/c/f1bed05a832ae79be5f7a105da56810eaa59a5f1