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NVD / CVE Program· CNA Linux

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

Noroxi assessment

Priority: Monitor (action score 28/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.08% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 206121294b9cf27f0589857f80d64f87e496ffb2, 30ab358fad0c7daa1d282ec48089901b21b36a20, 672b526def1f94c1be8eb11b885b803da0d8c2f1; azl3 kernel 6.6.134.1-2 on Azure Linux 3.0 6.6.137.1-1.

Low priority for now. Upgrade to Linux Linux 206121294b9cf27f0589857f80d64f87e496ffb2, 30ab358fad0c7daa1d282ec48089901b21b36a20, 672b526def1f94c1be8eb11b885b803da0d8c2f1; azl3 kernel 6.6.134.1-2 on Azure Linux 3.0 6.6.137.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.1 · v3.1—No exploit Fix available
Published
Apr 20, 2026
Updated
Nov 5, 2026
EPSS
0.0% · 0th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.0%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-31430

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel6.4 and later · before 6.6.135
  • linux linux kernel6.7 and later · before 6.12.82
  • linux linux kernel6.13 and later · before 6.18.23
  • linux linux kernel6.19 and later · before 6.19.13
  • linux linux kernel7.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 6.4affected
    • 30eae2b037af54b24109dcaea21db46f6285c69b and later · before 672b526def1f94c1be8eb11b885b803da0d8c2f1affected · git
    • 30eae2b037af54b24109dcaea21db46f6285c69b and later · before 30ab358fad0c7daa1d282ec48089901b21b36a20affected · git
    • 30eae2b037af54b24109dcaea21db46f6285c69b and later · before 206121294b9cf27f0589857f80d64f87e496ffb2affected · git
    • 30eae2b037af54b24109dcaea21db46f6285c69b and later · before 7fb4dadc2734f4020d7543d688b8d49c8e569c61affected · git
    • 30eae2b037af54b24109dcaea21db46f6285c69b and later · before d702c3408213bb12bd570bb97204d8340d141c51affected · git
    • before 6.4not affected · semver
    • 6.6.135 and later · up to and including 6.6.*not affected · semver
    • 6.12.82 and later · up to and including 6.12.*not affected · semver
    • 6.18.23 and later · up to and including 6.18.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:13linuxbefore 6.12.85-16.12.85-1
Debian:14linuxbefore 6.19.13-16.19.13-1
SUSE:Linux Enterprise Live Patching 15 SP7kernel-livepatch-SLE15-SP7_Update_19before 1-150700.15.3.41-150700.15.3.4
SUSE:Linux Enterprise Live Patching 15 SP7kernel-livepatch-SLE15-SP7-RT_Update_18before 1-150700.1.5.11-150700.1.5.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7kernel-64kbbefore 6.4.0-150700.53.73.26.4.0-150700.53.73.2
SUSE:Linux Enterprise Module for Basesystem 15 SP7kernel-defaultbefore 6.4.0-150700.53.73.26.4.0-150700.53.73.2
SUSE:Linux Enterprise Module for Basesystem 15 SP7kernel-default-basebefore 6.4.0-150700.53.73.2.150700.17.41.46.4.0-150700.53.73.2.150700.17.41.4
SUSE:Linux Enterprise Module for Basesystem 15 SP7kernel-sourcebefore 6.4.0-150700.53.73.16.4.0-150700.53.73.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7kernel-zfcpdumpbefore 6.4.0-150700.53.73.26.4.0-150700.53.73.2
SUSE:Linux Enterprise Module for Development Tools 15 SP7kernel-docsbefore 6.4.0-150700.53.73.16.4.0-150700.53.73.1
SUSE:Linux Enterprise Module for Development Tools 15 SP7kernel-obs-buildbefore 6.4.0-150700.53.73.26.4.0-150700.53.73.2
SUSE:Linux Enterprise Module for Development Tools 15 SP7kernel-symsbefore 6.4.0-150700.53.73.16.4.0-150700.53.73.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP7kernel-azurebefore 6.4.0-150700.53.73.26.4.0-150700.53.73.2
SUSE:Linux Micro 6.1kernel-defaultbefore 6.4.0-51.16.4.0-51.1
SUSE:Linux Micro 6.1kernel-kvmsmallbefore 6.4.0-51.16.4.0-51.1
SUSE:Linux Micro 6.1kernel-rtbefore 6.4.0-51.16.4.0-51.1
SUSE:Linux Micro 6.1kernel-sourcebefore 6.4.0-51.16.4.0-51.1
SUSE:Linux Micro 6.1kernel-source-rtbefore 6.4.0-51.16.4.0-51.1
SUSE:Real Time Module 15 SP7kernel-rtbefore 6.4.0-150700.7.67.16.4.0-150700.7.67.1
SUSE:Real Time Module 15 SP7kernel-source-rtbefore 6.4.0-150700.7.67.16.4.0-150700.7.67.1
SUSE:Real Time Module 15 SP7kernel-syms-rtbefore 6.4.0-150700.7.67.16.4.0-150700.7.67.1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-31428Apr 13, 2026 · netfilter: nfnetlink_log: fix uninitialized padding leak in NFULA_PAYLOAD
    22Monitor
  • ← EarlierCVE-2026-31429Apr 20, 2026 · net: skb: fix cross-cache free of KFENCE-allocated skb head
    22Monitor
  • Later →CVE-2026-31433Apr 22, 2026 · ksmbd: fix potencial OOB in get_file_all_info() for compound requests
    35Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux206121294b9cf27f0589857f80d64f87e496ffb2Vendor (CNA)
Linux Linux30ab358fad0c7daa1d282ec48089901b21b36a20Vendor (CNA)
Linux Linux672b526def1f94c1be8eb11b885b803da0d8c2f1Vendor (CNA)
Linux Linux7fb4dadc2734f4020d7543d688b8d49c8e569c61Vendor (CNA)
Linux Linuxd702c3408213bb12bd570bb97204d8340d141c51Vendor (CNA)
azl3 kernel 6.6.134.1-2 on Azure Linux 3.06.6.137.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.12.85-1 · Debian:13Package registry (OSV)
suse:kernel-64kb6.4.0-150700.53.73.2 · SUSE:Linux Enterprise Module for Basesystem 15 SP7Package registry (OSV)
suse:kernel-default6.4.0-51.1 · SUSE:Linux Micro 6.1Package registry (OSV)
suse:kernel-default-base6.4.0-150700.53.73.2.150700.17.41.4 · SUSE:Linux Enterprise Module for Basesystem 15 SP7Package registry (OSV)
suse:kernel-docs6.4.0-150700.53.73.1 · SUSE:Linux Enterprise Module for Development Tools 15 SP7Package registry (OSV)
suse:kernel-kvmsmall6.4.0-51.1 · SUSE:Linux Micro 6.1Package registry (OSV)
suse:kernel-livepatch-SLE15-SP7-RT_Update_181-150700.1.5.1 · SUSE:Linux Enterprise Live Patching 15 SP7Package registry (OSV)
suse:kernel-obs-build6.4.0-150700.53.73.2 · SUSE:Linux Enterprise Module for Development Tools 15 SP7Package registry (OSV)
suse:kernel-rt6.4.0-51.1 · SUSE:Linux Micro 6.1Package registry (OSV)
suse:kernel-source6.4.0-51.1 · SUSE:Linux Micro 6.1Package registry (OSV)
suse:kernel-source-rt6.4.0-51.1 · SUSE:Linux Micro 6.1Package registry (OSV)
suse:kernel-syms-rt6.4.0-150700.7.67.1 · SUSE:Real Time Module 15 SP7Package registry (OSV)
suse:kernel-zfcpdump6.4.0-150700.53.73.2 · SUSE:Linux Enterprise Module for Basesystem 15 SP7Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records