CVE-2026-31430 Details
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.
A vulnerability has been identified in the Linux kernel's handling of X.509 certificates, specifically when parsing extensions related to Basic Constraints and Key Usage. The issue arises because the parser reads the first byte of these extensions before verifying their length, leading to an out-of-bounds access. This vulnerability can be exploited by an unprivileged user who submits a specially crafted certificate to the kernel via the keyrings API. The problem has been demonstrated with a proof-of-concept program that was responsibly disclosed.
Users can upgrade to the patched version of the Linux kernel available in the Linux kernel stable tree.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://git.kernel.org/stable/c/206121294b9cf27f0589857f80d64f87e496ffb2 | kernel.org | Patch |
| https://git.kernel.org/stable/c/30ab358fad0c7daa1d282ec48089901b21b36a20 | kernel.org | Patch |
| https://git.kernel.org/stable/c/672b526def1f94c1be8eb11b885b803da0d8c2f1 | kernel.org | Patch |
| https://git.kernel.org/stable/c/7fb4dadc2734f4020d7543d688b8d49c8e569c61 | kernel.org | Patch |
| https://git.kernel.org/stable/c/d702c3408213bb12bd570bb97204d8340d141c51 | kernel.org | Patch |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-125 | Out-of-bounds Read | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| linux linux kernel | >= 6.4, < 6.6.135 >= 6.7, < 6.12.82 >= 6.13, < 6.18.23 >= 6.19, < 6.19.13 7.0 rc1 7.0 rc2 7.0 rc3 7.0 rc4 7.0 rc5 7.0 rc6 7.0 rc7 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | kernel.org |
| May 21, 2026 | Initial Analysis | [email protected] |
| Apr 20, 2026 | New CVE Received | kernel.org |