CVE-2026-42013

HIGHPre-NVD 8.28.2—
EchelonGraph scoreMEDIUM confidence

Score 8.2 from GitHub Security Advisory (severity: HIGH) published 2026-05-27. a secondary CVSS source baseline 8.2; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
8.2
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.2Exploit: NoneExposed: 0

A fix is available — apply it.

A flaw was found in gnutls. When validating certificates, an oversized Subject Alternative Name (SAN) could cause the validation process to incorrectly fall back to checking the Common Name (CN) field. This could allow a remote attacker to bypass proper certificate validation, potentially leading to spoofing or man-in-the-middle attacks.

CVSS v3
8.2
EG Score
8.2(medium)
EG Risk
52(Track)
EG Risk 52/100SSVC: 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
Severity82% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
34.6%
KEV
Not listed

Published

May 26, 2026

Last Modified

July 22, 2026

Advisory Details (3)

Auto-updated May 28, 2026
Patch available. Sources: redhat.
redhat

2467448 – (CVE-2026-42013) CVE-2026-42013 gnutls: gnutls: Certificate validation bypass due to oversized Subject Alternative Name

https://bugzilla.redhat.com/show_bug.cgi?id=2467448
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-42013
redhat Patch Available

Affected: Red Hat Enterprise Linux 8.

https://access.redhat.com/errata/RHSA-2026:20611

Vendor Advisories for CVE-2026-42013(17)

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

Patch Availability(12)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulibgnutls30t64 (3.8.12-2ubuntu1.1) @ resolute2026-07-01ubuntu
redhatlibtasn1-0:4.13-3.el8_6.22026-06-29redhat
redhatlibtasn1-0:4.13-3.el8_4.12026-06-29redhat
redhatlibtasn1-0:4.13-4.el8_8.12026-06-29redhat
redhatgnutls-0:3.8.3-4.el9_4.62026-06-29redhat
redhatgnutls-0:3.8.3-6.el9_6.42026-06-25redhat
redhatdiscovery/discovery-ui-rhel9:17821669522026-06-24redhat
redhatrhui5/rhua-rhel9:17815257392026-06-16redhat
redhatgnutls-0:3.8.9-9.el10_0.192026-06-16redhat
redhatgnutls-0:3.8.10-4.el10_22026-05-26redhat
redhatgnutls-0:3.8.10-4.el9_82026-05-26redhat
redhatgnutls-0:3.6.16-8.el8_10.62026-05-26redhat

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(2)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 7× in last 7d / 51× 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 170 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-42013?
CVE-2026-42013 is a high vulnerability published on May 26, 2026. A flaw was found in gnutls. When validating certificates, an oversized Subject Alternative Name (SAN) could cause the validation process to incorrectly fall back to checking the Common Name (CN) field. This could allow a remote attacker to bypass proper certificate validation, potentially leading…
When was CVE-2026-42013 disclosed?
CVE-2026-42013 was first published in the National Vulnerability Database on May 26, 2026, with the most recent update on July 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42013 actively exploited?
CVE-2026-42013 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 34.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-42013?
CVE-2026-42013 has a CVSS v3 base score of 8.2 (NVD).
How do I remediate CVE-2026-42013?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42013, 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.

Dependency Blast Radius

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