CVE-2026-31430

high

Published 2026-04-20 · Modified 2026-05-21

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CVSS v3

7.1

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

CVSS v4 NEW

—

not yet in upstream

VIR risk

7.1

Description

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.

Predictions

Exploit likelihood

70%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

Mitigation details

Source: Debian Security Tracker · View original ↗ · DFSG

CVE-2026-31430 NameCVE-2026-31430 DescriptionIn 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…

CVE-2026-31430

Name	CVE-2026-31430
Description	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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DSA-6238-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
linux (PTS)	bullseye	5.10.223-1	fixed
	bullseye (security)	5.10.257-1	fixed
	bookworm	6.1.170-3	fixed
	bookworm (security)	6.1.174-1	fixed
	trixie	6.12.86-1	fixed
	trixie (security)	6.12.90-2	fixed
	forky	7.0.9-1	fixed
	sid	7.0.10-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Origin
linux	source	bullseye	(not affected)
linux	source	bookworm	(not affected)
linux	source	trixie	6.12.85-1	DSA-6238-1
linux	source	(unstable)	6.19.13-1

Notes

[bookworm] - linux <not-affected> (Vulnerable code not present)
[bullseye] - linux <not-affected> (Vulnerable code not present)
https://git.kernel.org/linus/d702c3408213bb12bd570bb97204d8340d141c51 (7.0)

Home - Debian Security - Source (Git)

Apply commands

text fix

Notes

[bookworm] - linux <not-affected> (Vulnerable code not present)[bullseye] - linux <not-affected> (Vulnerable code not present)https://git.kernel.org/linus/d702c3408213bb12bd570bb97204d8340d141c51 (7.0)

OS impact

OS	Version	Status	Fixed in
sles		affected
debian	bookworm	fixed	`0`
debian	bullseye	fixed	`0`
debian	forky	fixed	`6.19.13-1`
debian	sid	fixed	`6.19.13-1`
debian	trixie	fixed	`6.12.85-1`
linux-kernel		affected	`6.6.135`
linux-kernel	7.0	affected

Application impact

Vendor	Product	Versions	Fixed
google	gcp

References

CWEs

CWE-125

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.