CVE-2026-31430
Published: April 21, 2026Last modified: May 1, 2026
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.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 7.1 |
| Attack Vector | LOCAL |
| Attack complexity | LOW |
| Privileges required | LOW |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity impact | NONE |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Not affected (6.1.33-r0) |
| 25 LTS | linux-lts | Fixed (6.12.85-r0) | |
| Stream | linux-lts | Fixed (6.12.85-r0) |
References
- https://git.kernel.org/stable/c/206121294b9cf27f0589857f80d64f87e496ffb2
- https://git.kernel.org/stable/c/30ab358fad0c7daa1d282ec48089901b21b36a20
- https://git.kernel.org/stable/c/672b526def1f94c1be8eb11b885b803da0d8c2f1
- https://git.kernel.org/stable/c/7fb4dadc2734f4020d7543d688b8d49c8e569c61
- https://git.kernel.org/stable/c/d702c3408213bb12bd570bb97204d8340d141c51