CVE-2026-42508

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.1 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 71% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
9.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 9.1Exploit: NoneExposed: 0

A fix is available — apply it.

Previously, a revoked 'SignatureKey' belonging to a CA was not correctly checked for revocation. Now, both the 'key' and 'key.SignatureKey' are checked for @revoked.

CVSS v3
9.1
EG Score
9.1(medium)
EPSS
38.7%
KEV
Not listed

Published

May 22, 2026

Last Modified

July 16, 2026

Advisory Details (4)

Auto-updated May 28, 2026
No patch confirmed yet.
generic

GO-2026-5021 - Go Packages

https://pkg.go.dev/vuln/GO-2026-5021
generic
https://groups.google.com/g/golang-announce/c/a082jnz-LvI
generic

x/crypto/ssh/knownhosts: failure to enforce `@revoked` status · Issue #79568 · golang/go · GitHub

https://go.dev/issue/79568
generic
https://go.dev/cl/781220

Vendor Advisories for CVE-2026-42508(19)

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

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulxd-tools (2.0.11-0ubuntu1~16.04.4+esm3) @ xenial2026-06-29ubuntu
redhatgolang1-25-main-1.25.11-2.hum12026-06-04redhat
redhatgolang1-26-main-1.26.4-2.hum12026-06-04redhat

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

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFixed inDependents
golang.org/x/crypto—0.52.0—

Weakness Classification(1)

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 / 77× 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 286 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-42508?
CVE-2026-42508 is a critical vulnerability published on May 22, 2026. Previously, a revoked 'SignatureKey' belonging to a CA was not correctly checked for revocation. Now, both the 'key' and 'key.SignatureKey' are checked for @revoked.
When was CVE-2026-42508 disclosed?
CVE-2026-42508 was first published in the National Vulnerability Database on May 22, 2026, with the most recent update on July 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42508 actively exploited?
CVE-2026-42508 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 38.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-42508?
CVE-2026-42508 has a CVSS v3.1 base score of 9.1 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-42508?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42508, 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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