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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux30eae2b037af54b24109dcaea21db46f6285c69b < 672b526def1f94c1be8eb11b885b803da0d8c2f1affected
LinuxLinux30eae2b037af54b24109dcaea21db46f6285c69b < 30ab358fad0c7daa1d282ec48089901b21b36a20affected
LinuxLinux30eae2b037af54b24109dcaea21db46f6285c69b < 206121294b9cf27f0589857f80d64f87e496ffb2affected
LinuxLinux30eae2b037af54b24109dcaea21db46f6285c69b < 7fb4dadc2734f4020d7543d688b8d49c8e569c61affected
LinuxLinux30eae2b037af54b24109dcaea21db46f6285c69b < d702c3408213bb12bd570bb97204d8340d141c51affected
LinuxLinux6.4affected
LinuxLinux0 < 6.4unaffected
LinuxLinux6.6.135 <= 6.6.*unaffected
LinuxLinux6.12.82 <= 6.12.*unaffected
LinuxLinux6.18.23 <= 6.18.*unaffected
LinuxLinux6.19.13 <= 6.19.*unaffected
LinuxLinux7.0 <= *unaffected

Weaknesses

References