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
Trending — 4 sources updated this week
8.2EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.2Exploit: None knownExposed: 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 PROB
0%
EPSS %ILE
36%
KEV
Not listed

Published

May 26, 2026

Last Modified

September 3, 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(20)

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

Patch Availability(22)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulibgnutlsxx28 (3.7.3-4ubuntu1.9) @ jammy2026-09-14ubuntu
ubuntulibgnutlsxx28 (3.4.10-4ubuntu1.9+esm4) @ xenial2026-09-14ubuntu
redhatrhcos-417.94.202608250221-02026-09-03redhat
redhatrhcos-412.86.202608241157-02026-09-03redhat
redhatrhcos-416.94.202608150307-02026-08-31redhat
redhatrhcos-418.94.202608142238-02026-08-26redhat
redhatrhui5/rhua-tp-rhel9:17872412602026-08-24redhat
redhatgnutls-0:3.3.29-9.el7_9.22026-07-22redhat
redhatrhcos-4.19.9.6.202607151909-02026-07-22redhat
redhatgnutls-0:3.7.6-21.el9_2.72026-07-20redhat
redhatlibtasn1-0:4.13-3.el8_6.22026-06-29redhat
redhatgnutls-0:3.8.3-4.el9_4.62026-06-29redhat
redhatlibtasn1-0:4.13-4.el8_8.12026-06-29redhat
redhatlibtasn1-0:4.13-3.el8_4.12026-06-29redhat
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.el9_82026-05-26redhat
redhatgnutls-0:3.8.10-4.el10_22026-05-26redhat
redhatgnutls-0:3.6.16-8.el8_10.62026-05-26redhat
redhatgnutls-main-3.8.13-1.hum12026-05-02redhat

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.

Affected Packages

(9 across 9 ecosystems)
Alpine:v3.20(1)
PackageVulnerable rangeFixed inDependents
gnutls—3.8.13-r0—
Alpine:v3.21(1)
PackageVulnerable rangeFixed inDependents
gnutls—3.8.13-r0—
Alpine:v3.22(1)
PackageVulnerable rangeFixed inDependents
gnutls—3.8.13-r0—
Alpine:v3.23(1)
PackageVulnerable rangeFixed inDependents
gnutls—3.8.13-r0—
Alpine:v3.24(1)
PackageVulnerable rangeFixed inDependents
gnutls—3.8.13-r0—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
gnutls283.7.1-5 ... 3.7.1-5+deb11u9 (10 versions)3.7.1-5+deb11u10—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
gnutls283.7.9-2 ... 3.7.9-2+deb12u6 (7 versions)3.7.9-2+deb12u7—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
gnutls283.8.9-3, 3.8.9-3+deb13u1, 3.8.9-3+deb13u2, 3.8.9-3+deb13u33.8.9-3+deb13u4—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
gnutls283.8.10-1 ... 3.8.9-3 (11 versions)3.8.13-1—

Weakness Classification(2)

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

Additional Vendor Advisories

(4)

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 9× in last 7d / 79× 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 347 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

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 September 3, 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 0% probability of exploitation in the next 30 days, which ranks it in the top 64.3% of all scored CVEs.
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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-42013

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