Out-of-bounds Read in Linux
CVE-2026-31430
In the Linux kernel, the following vulnerability has been resolved: X.509: Fix out-of-bounds access when parsing extensions Leo reports an out-of-bounds access when parsing a certificate with empty Basic Constraints or Key Usage extension because the first byte of the extension is read before checking its length. Fix it. The bug can be triggered by an unprivileged user by submitting a specially crafted certificate to the kernel through the keyrings(7) API. Leo has demonstrated this with a proof-of-concept program responsibly disclosed off-list.
Vulnerability class: Buffer Overflow
EPSS: 0.001 (0.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H.
Affected products
- Linux — versions 30eae2b037af54b24109dcaea21db46f6285c69b, 6.4, 0
- Linux Linux_kernel — versions 7.0
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-31430?
- CVE-2026-31430 is a high-severity vulnerability in Linux, classified under Out-of-bounds Read. CVSS score: 7.1/10. Published 2026-04-20.
- How severe is CVE-2026-31430?
- High severity. CVSS v3 base score is 7.1 out of 10.