CVE-2026-31430

HIGHNVD 7.17.1—
EchelonGraph scoreMEDIUM confidence

Score 7.1 from GitHub Security Advisory (severity: HIGH) published 2026-04-20. NVD baseline CVSS 7.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
7.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.1Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
7.1
EG Score
7.1(medium)
EG Risk
36(Track)
EG Risk 36/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity71% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
0%
KEV
Not listed

Published

April 20, 2026

Last Modified

May 21, 2026

Advisory Details (5)

Auto-updated Jun 14, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic🟡 PoC Available

X.509: Fix out-of-bounds access when parsing extensions - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/d702c3408213bb12bd570bb97204d8340d141c51
generic🟡 PoC Available

X.509: Fix out-of-bounds access when parsing extensions - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7fb4dadc2734f4020d7543d688b8d49c8e569c61
generic🟡 PoC Available

X.509: Fix out-of-bounds access when parsing extensions - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/672b526def1f94c1be8eb11b885b803da0d8c2f1
generic🟡 PoC Available

X.509: Fix out-of-bounds access when parsing extensions - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/30ab358fad0c7daa1d282ec48089901b21b36a20
generic🟡 PoC Available

X.509: Fix out-of-bounds access when parsing extensions - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/206121294b9cf27f0589857f80d64f87e496ffb2

Vendor Advisories for CVE-2026-31430(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 6.6.135—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 29× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 133 total refreshes for this CVE.

  1. 2026-07-26 14:54 UTCEPSS rescore
  2. 2026-07-26 14:54 UTCEPSS rescore
  3. 2026-07-25 14:18 UTCEPSS rescore
  4. 2026-07-25 14:17 UTCEPSS rescore
  5. 2026-07-24 14:17 UTCEPSS rescore
  6. 2026-07-23 03:08 UTCEG score recompute
  7. 2026-07-22 14:08 UTCEPSS rescore
  8. 2026-07-22 14:08 UTCEPSS rescore
  9. 2026-07-20 07:04 UTCOSV refresh
  10. 2026-07-18 10:04 UTCEPSS rescore
  11. 2026-07-18 10:04 UTCEPSS rescore
  12. 2026-07-16 17:03 UTCEPSS rescore
  13. 2026-07-16 17:03 UTCEPSS rescore
  14. 2026-07-15 16:57 UTCEPSS rescore
  15. 2026-07-15 16:57 UTCEPSS rescore
  16. 2026-07-13 22:30 UTCEPSS rescore
  17. 2026-07-13 06:13 UTCEPSS rescore
  18. 2026-07-13 06:13 UTCEPSS rescore
  19. 2026-07-11 08:27 UTCEPSS rescore
  20. 2026-07-09 19:10 UTCEPSS rescore
  21. 2026-07-08 15:15 UTCEPSS rescore
  22. 2026-07-07 13:46 UTCEPSS rescore
  23. 2026-07-06 16:27 UTCEPSS rescore
  24. 2026-07-06 16:27 UTCEPSS rescore
  25. 2026-07-06 02:23 UTCEPSS rescore
Show 75 more
  1. 2026-07-06 02:23 UTCEPSS rescore
  2. 2026-07-04 06:31 UTCEPSS rescore
  3. 2026-06-29 14:06 UTCEPSS rescore
  4. 2026-06-29 14:06 UTCEPSS rescore
  5. 2026-06-28 14:07 UTCEPSS rescore
  6. 2026-06-28 14:07 UTCEPSS rescore
  7. 2026-06-28 04:56 UTCEPSS rescore
  8. 2026-06-28 04:56 UTCEPSS rescore
  9. 2026-06-27 03:08 UTCEPSS rescore
  10. 2026-06-24 14:05 UTCEPSS rescore
  11. 2026-06-23 21:33 UTCEPSS rescore
  12. 2026-06-23 21:33 UTCEPSS rescore
  13. 2026-06-21 01:59 UTCEPSS rescore
  14. 2026-06-18 17:52 UTCEPSS rescore
  15. 2026-06-18 17:52 UTCEPSS rescore
  16. 2026-06-17 17:53 UTCEPSS rescore
  17. 2026-06-15 17:49 UTCEPSS rescore
  18. 2026-06-14 23:18 UTCEPSS rescore
  19. 2026-06-14 19:06 UTCVendor advisory
  20. 2026-06-14 19:06 UTCGHSA enrichment
  21. 2026-06-13 23:00 UTCEPSS rescore
  22. 2026-06-12 23:12 UTCEPSS rescore
  23. 2026-06-12 23:12 UTCEPSS rescore
  24. 2026-06-12 05:36 UTCVendor advisory
  25. 2026-06-12 05:36 UTCGHSA enrichment
  26. 2026-06-11 18:37 UTCVendor advisory
  27. 2026-06-11 18:37 UTCGHSA enrichment
  28. 2026-06-11 14:00 UTCEPSS rescore
  29. 2026-06-10 22:18 UTCEPSS rescore
  30. 2026-06-10 14:06 UTCVendor advisory
  31. 2026-06-10 14:06 UTCGHSA enrichment
  32. 2026-06-10 13:22 UTCEPSS rescore
  33. 2026-06-10 03:07 UTCVendor advisory
  34. 2026-06-10 03:07 UTCGHSA enrichment
  35. 2026-06-09 16:09 UTCVendor advisory
  36. 2026-06-09 16:09 UTCGHSA enrichment
  37. 2026-06-09 05:12 UTCVendor advisory
  38. 2026-06-09 05:12 UTCGHSA enrichment
  39. 2026-06-08 14:17 UTCEPSS rescore
  40. 2026-06-08 14:17 UTCEPSS rescore
  41. 2026-06-08 13:52 UTCVendor advisory
  42. 2026-06-08 13:52 UTCGHSA enrichment
  43. 2026-06-08 02:47 UTCVendor advisory
  44. 2026-06-08 02:47 UTCGHSA enrichment
  45. 2026-06-07 15:49 UTCVendor advisory
  46. 2026-06-07 15:49 UTCGHSA enrichment
  47. 2026-06-07 15:25 UTCEPSS rescore
  48. 2026-06-07 15:25 UTCEPSS rescore
  49. 2026-06-07 15:25 UTCEPSS rescore
  50. 2026-06-07 04:48 UTCVendor advisory
  51. 2026-06-07 04:48 UTCGHSA enrichment
  52. 2026-06-06 13:47 UTCEPSS rescore
  53. 2026-06-06 13:47 UTCEPSS rescore
  54. 2026-06-06 09:13 UTCVendor advisory
  55. 2026-06-06 09:13 UTCGHSA enrichment
  56. 2026-06-05 22:47 UTCEPSS rescore
  57. 2026-06-05 22:47 UTCEPSS rescore
  58. 2026-06-05 22:15 UTCVendor advisory
  59. 2026-06-05 22:15 UTCGHSA enrichment
  60. 2026-06-05 07:38 UTCVendor advisory
  61. 2026-06-05 07:38 UTCGHSA enrichment
  62. 2026-06-04 18:50 UTCVendor advisory
  63. 2026-06-04 18:50 UTCGHSA enrichment
  64. 2026-06-04 13:12 UTCEPSS rescore
  65. 2026-06-04 13:12 UTCEPSS rescore
  66. 2026-06-03 16:14 UTCVendor advisory
  67. 2026-06-03 16:14 UTCGHSA enrichment
  68. 2026-06-03 00:23 UTCVendor advisory
  69. 2026-06-03 00:23 UTCGHSA enrichment
  70. 2026-06-02 20:13 UTCEPSS rescore
  71. 2026-06-02 20:13 UTCEPSS rescore
  72. 2026-06-02 13:25 UTCVendor advisory
  73. 2026-06-02 13:25 UTCGHSA enrichment
  74. 2026-06-01 16:47 UTCEG score recompute▲ 7.10
  75. 2026-06-01 16:47 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-31430?
CVE-2026-31430 is a high vulnerability published on April 20, 2026. 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…
When was CVE-2026-31430 disclosed?
CVE-2026-31430 was first published in the National Vulnerability Database on April 20, 2026, with the most recent update on May 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-31430 actively exploited?
CVE-2026-31430 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 99.8% of all scored CVEs.
What is the CVSS score of CVE-2026-31430?
CVE-2026-31430 has a CVSS v3 base score of 7.1 (NVD).
How do I remediate CVE-2026-31430?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-31430, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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