PT-2026-33747 · Linux · Linux

Published 2026-04-20 · Updated 2026-04-20 · CVE-2026-31430

NVD

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.

Related Identifiers

CVE-2026-31430

Affected Products

Linux

References · 6

• https://nvd.nist.gov/vuln/detail/CVE-2026-31430 · Security Note
• https://git.kernel.org/stable/c/d702c3408213bb12bd570bb97204d8340d141c51 · Note
• https://git.kernel.org/stable/c/30ab358fad0c7daa1d282ec48089901b21b36a20 · Note
• https://git.kernel.org/stable/c/672b526def1f94c1be8eb11b885b803da0d8c2f1 · Note
• https://git.kernel.org/stable/c/206121294b9cf27f0589857f80d64f87e496ffb2 · Note
• https://git.kernel.org/stable/c/7fb4dadc2734f4020d7543d688b8d49c8e569c61 · Note