CVE-2026-31430

Summary

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.

Impact & exploitability

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Affected products we track (1)

Recommendation

Apply the vendor fix promptly. Open any affected product above for its exact safe version.

Official patch: https://git.kernel.org/stable/c/206121294b9cf27f0589857f80d64f87e496ffb2 ↗

Additional information

• NVD record
• https://git.kernel.org/stable/c/206121294b9cf27f0589857f80d64f87e496ffb2Patch
• https://git.kernel.org/stable/c/30ab358fad0c7daa1d282ec48089901b21b36a20Patch
• https://git.kernel.org/stable/c/672b526def1f94c1be8eb11b885b803da0d8c2f1Patch
• https://git.kernel.org/stable/c/7fb4dadc2734f4020d7543d688b8d49c8e569c61Patch
• https://git.kernel.org/stable/c/d702c3408213bb12bd570bb97204d8340d141c51Patch