CVE-2026-31430
kernel: X.509: Fix out-of-bounds access when parsing extensions
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · April 20, 2026
Updated · October 29, 2026
Description
A flaw was found in the Linux kernel. An unprivileged user can exploit this vulnerability by submitting a specially crafted X.509 certificate to the kernel through the keyrings(7) application programming interface (API). This certificate, specifically when containing empty Basic Constraints or Key Usage extensions, can trigger an out-of-bounds access during parsing. An out-of-bounds access is a memory corruption issue where a program attempts to read or write data beyond the allocated memory region, which can lead to system instability or a denial of service.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.1 · 6.6CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:L
CWE-125 · Out-of-bounds Read