High 7.1Published Apr 20, 2026

CVE-2026-31430X.509: Fix out-of-bounds access when parsing extensions

Updated under an hour ago (Oct 27, 2026, 4:00 AM ET)

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Exploited in the last 30 days

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.

CVSS: 7.1 HIGH (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Analyzed
Record last updated: May 11, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 30eae2b037af54b24109dcaea21db46f6285c69b before 672b526def1f94c1be8eb11b885b803da0d8c2f1; 30eae2b037af54b24109dcaea21db46f6285c69b builds before 30ab358fad0c7daa1d282ec48089901b21b36a20; from 30eae2b037af54b24109dcaea21db46f6285c69b before 206121294b9cf27f0589857f80d64f87e496ffb2; 30eae2b037af54b24109dcaea21db46f6285c69b builds before 7fb4dadc2734f4020d7543d688b8d49c8e569c61; from 30eae2b037af54b24109dcaea21db46f6285c69b before d702c3408213bb12bd570bb97204d8340d141c51	CNA record
linux linux_kernel linux:linux_kernel	from 6.4 before 6.6.135; from 6.7 before 6.12.82; from 6.13 before 6.18.23; from 6.19 before 6.19.13; 7.0; 7.0; 7.0; 7.0; and 3 more ranges	NVD

References

References

https://git.kernel.org/stable/c/672b526def1f94c1be8eb11b885b803da0d8c2f1	patch
https://git.kernel.org/stable/c/30ab358fad0c7daa1d282ec48089901b21b36a20	patch
https://git.kernel.org/stable/c/206121294b9cf27f0589857f80d64f87e496ffb2	patch
https://git.kernel.org/stable/c/7fb4dadc2734f4020d7543d688b8d49c8e569c61	patch
https://git.kernel.org/stable/c/d702c3408213bb12bd570bb97204d8340d141c51	patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.