CVE-2026-74938

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2026-08-18. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 3 sources updated this week
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.1Exploit: None knownExposed: 0

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

Mitigation bypass in the JavaScript: GC component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.

CVSS v3
9.1
EG Score
9.1(medium)
EG Risk
56(Track)
EG Risk 56/100SSVC: 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
Severity91% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
25%
KEV
Not listed

Published

August 18, 2026

Last Modified

August 19, 2026

Advisory Details (5)

Auto-updated Sep 15, 2026
No patch confirmed yet.
generic

Security Vulnerabilities fixed in Thunderbird 153.1 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-80/
generic

Security Vulnerabilities fixed in Thunderbird 154 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-78/
generic

Security Vulnerabilities fixed in Firefox ESR 153.1 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-77/
generic

Security Vulnerabilities fixed in Firefox 154 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-74/
generic

Access Denied

https://bugzilla.mozilla.org/show_bug.cgi?id=2053688

Vendor Advisories for CVE-2026-74938(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 46× in last 7d / 203× 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 230 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-74938?
CVE-2026-74938 is a critical vulnerability published on August 18, 2026. Mitigation bypass in the JavaScript: GC component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.
When was CVE-2026-74938 disclosed?
CVE-2026-74938 was first published in the National Vulnerability Database on August 18, 2026, with the most recent update on August 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-74938 actively exploited?
CVE-2026-74938 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 74.5% of all scored CVEs.
What is the CVSS score of CVE-2026-74938?
CVE-2026-74938 has a CVSS v3.1 base score of 9.1 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-74938?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-74938, 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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