CyberSecBulletin
CVE-2026-31430NVD status: Analyzed

Linux: Out-of-bounds Read

Published Updated By the CyberSecBulletin desk

CVE-2026-31430 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 672b526def1f94c1be8eb11b885b803da0d8c2f1, 30ab358fad0c7daa1d282ec48089901b21b36a20, 206121294b9cf27f0589857f80d64f87e496ffb2 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.08% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 672b526def1f94c1be8eb11b885b803da0d8c2f1 or 30ab358fad0c7daa1d282ec48089901b21b36a20 or 206121294b9cf27f0589857f80d64f87e496ffb2 or 7fb4dadc2734f4020d7543d688b8d49c8e569c61, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.6.135 or 6.12.82 or 6.18.23 or 6.19.13, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux30eae2b037af54b24109dcaea21db46f6285c69b up to, but not including, 672b526def1f94c1be8eb11b885b803da0d8c2f1; 30eae2b037af54b24109dcaea21db46f6285c69b up to, but not including, 30ab358fad0c7daa1d282ec48089901b21b36a20; 30eae2b037af54b24109dcaea21db46f6285c69b up to, but not including, 206121294b9cf27f0589857f80d64f87e496ffb2; 30eae2b037af54b24109dcaea21db46f6285c69b up to, but not including, 7fb4dadc2734f4020d7543d688b8d49c8e569c61; 30eae2b037af54b24109dcaea21db46f6285c69b up to, but not including, d702c3408213bb12bd570bb97204d8340d141c51; 6.4672b526def1f94c1be8eb11b885b803da0d8c2f1, 30ab358fad0c7daa1d282ec48089901b21b36a20, 206121294b9cf27f0589857f80d64f87e496ffb2, 7fb4dadc2734f4020d7543d688b8d49c8e569c61, d702c3408213bb12bd570bb97204d8340d141c51
LinuxLinux Kernel6.4 up to, but not including, 6.6.135; 6.7 up to, but not including, 6.12.82; 6.13 up to, but not including, 6.18.23; 6.19 up to, but not including, 6.19.13; 7.06.6.135, 6.12.82, 6.18.23, 6.19.13

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H. Scored by NVD.

Official 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: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that provides appropriate memory abstractions.

More Out-of-bounds Read vulnerabilities (CWE-125)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Read vulnerabilities

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