CVE-2026-74976

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

Score 6.5 from GitHub Security Advisory published 2026-08-18. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 4 sources updated this week
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: None knownExposed: 0

A fix is available — apply it.

JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: 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
Severity65% × 45%
Exploitation0% × 40%
Automatability0% × 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 (7)

Auto-updated Aug 19, 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 140.14 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-79/
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 ESR 140.14 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-76/
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=1952164

Vendor Advisories for CVE-2026-74976(16)

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

Patch Availability(21)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatfirefox-0:140.14.0-1.el9_22026-09-09redhat
redhatthunderbird-0:140.14.0-1.el9_22026-09-09redhat
redhatthunderbird-0:140.14.0-1.el8_62026-09-09redhat
redhatthunderbird-0:140.14.0-1.el8_42026-09-09redhat
redhatthunderbird-0:140.14.0-1.el8_82026-09-09redhat
redhatfirefox-0:140.14.0-1.el9_42026-09-08redhat
redhatthunderbird-0:140.14.0-1.el8_102026-09-08redhat
redhatfirefox-0:140.14.0-1.el8_82026-09-08redhat
redhatthunderbird-0:140.14.0-1.el9_82026-09-08redhat
redhatthunderbird-0:140.14.0-1.el10_02026-09-08redhat
redhatfirefox-0:140.14.0-1.el7_92026-09-08redhat
redhatfirefox-0:140.14.0-1.el8_42026-09-08redhat
redhatfirefox-0:140.14.0-1.el9_62026-09-08redhat
redhatthunderbird-0:140.14.0-1.el10_22026-09-08redhat
redhatfirefox-0:140.14.0-1.el10_02026-09-08redhat
redhatfirefox-0:140.14.0-1.el8_62026-09-08redhat
redhatthunderbird-0:140.14.0-1.el9_42026-09-08redhat
redhatthunderbird-0:140.14.0-1.el9_62026-09-08redhat
redhatfirefox-0:140.14.0-1.el9_82026-08-24redhat
redhatfirefox-0:140.14.0-1.el8_102026-08-24redhat
redhatfirefox-0:140.14.0-1.el10_22026-08-24redhat

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

(6 across 3 ecosystems)
Debian:12(2)
PackageVulnerable rangeFixed inDependents
firefox-esr102.11.0esr-1 ... 140.9.1esr-1~deb13u1 (195 versions)140.14.0esr-1~deb12u1—
thunderbird1:102.11.0-1 ... 1:140.9.1esr-1~deb13u1 (224 versions)1:140.14.0esr-1~deb12u1—
Debian:13(2)
PackageVulnerable rangeFixed inDependents
firefox-esr128.13.0esr-1 ... 140.9.1esr-1~deb13u1 (71 versions)140.14.0esr-1~deb13u1—
thunderbird1:128.13.0esr-1 ... 1:140.9.1esr-1~deb13u1 (80 versions)1:140.14.0esr-1~deb13u1—
Debian:14(2)
PackageVulnerable rangeFixed inDependents
firefox-esr128.13.0esr-1 ... 140.9.1esr-1~deb13u1 (72 versions)140.14.0esr-2—
thunderbird1:128.13.0esr-1 ... 1:140.9.1esr-1~deb13u1 (81 versions)1:140.14.0esr-1—

Weakness Classification(1)

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

Additional Vendor Advisories

(6)

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 27× in last 7d / 108× 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 122 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-74976?
CVE-2026-74976 is a medium vulnerability published on August 18, 2026. JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
When was CVE-2026-74976 disclosed?
CVE-2026-74976 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-2026-74976 actively exploited?
CVE-2026-74976 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 74.8% of all scored CVEs.
What is the CVSS score of CVE-2026-74976?
CVE-2026-74976 has a CVSS v3.1 base score of 6.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-74976?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-74976, 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-2026-74976

Explore →

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