Linux Kernel X.509 OOB Access via Keyrings API (CVE-2026-31430)
CVE-2026-31430 Published on April 20, 2026
X.509: Fix out-of-bounds access when parsing extensions
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.
Products Associated with CVE-2026-31430
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Affected Versions
Linux:- Version 30eae2b037af54b24109dcaea21db46f6285c69b and below 672b526def1f94c1be8eb11b885b803da0d8c2f1 is affected.
- Version 30eae2b037af54b24109dcaea21db46f6285c69b and below 30ab358fad0c7daa1d282ec48089901b21b36a20 is affected.
- Version 30eae2b037af54b24109dcaea21db46f6285c69b and below 206121294b9cf27f0589857f80d64f87e496ffb2 is affected.
- Version 30eae2b037af54b24109dcaea21db46f6285c69b and below 7fb4dadc2734f4020d7543d688b8d49c8e569c61 is affected.
- Version 30eae2b037af54b24109dcaea21db46f6285c69b and below d702c3408213bb12bd570bb97204d8340d141c51 is affected.
- Version 6.4 is affected.
- Before 6.4 is unaffected.
- Version 6.6.135, <= 6.6.* is unaffected.
- Version 6.12.82, <= 6.12.* is unaffected.
- Version 6.18.23, <= 6.18.* is unaffected.
- Version 6.19.13, <= 6.19.* is unaffected.
- Version 7.0, <= * is unaffected.