CVE-2026-84118

MEDIUMPre-NVD 5.45.4—
EchelonGraph scoreHIGH confidence

Score 5.4 from GitHub Security Advisory published 2026-09-01. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 5.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 3 sources updated this week
5.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.4Exploit: None knownExposed: 0

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

Use-after-free in the JavaScript: GC component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.

CVSS v3
5.4
EG Score
5.4(high)
EG Risk
24(Track)
EG Risk 24/100SSVC: 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
Severity54% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
19%
KEV
Not listed

Published

September 1, 2026

Last Modified

September 2, 2026

Advisory Details (3)

Auto-updated Sep 1, 2026
No patch confirmed yet.
generic

Security Vulnerabilities fixed in Firefox ESR 153.2 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-85/
generic

Security Vulnerabilities fixed in Firefox 155 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-82/
generic

Access Denied

https://bugzilla.mozilla.org/show_bug.cgi?id=2057457

Vendor Advisories for CVE-2026-84118(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 18× in last 7d / 72× 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.

  1. 2026-09-24 15:56 UTCEG score recompute
  2. 2026-09-24 15:56 UTCGHSA enrichment
  3. 2026-09-24 14:04 UTCEPSS rescore
  4. 2026-09-23 17:54 UTCEPSS rescore
  5. 2026-09-23 17:04 UTCGHSA enrichment
  6. 2026-09-22 18:13 UTCEG score recompute
  7. 2026-09-22 18:13 UTCGHSA enrichment
  8. 2026-09-22 16:01 UTCEPSS rescore
  9. 2026-09-21 21:09 UTCEPSS rescore
  10. 2026-09-21 19:21 UTCGHSA enrichment
  11. 2026-09-20 20:30 UTCEG score recompute
  12. 2026-09-20 20:30 UTCGHSA enrichment
  13. 2026-09-20 20:16 UTCEPSS rescore
  14. 2026-09-19 21:39 UTCEG score recompute
  15. 2026-09-19 21:39 UTCGHSA enrichment
  16. 2026-09-18 22:49 UTCEG score recompute
  17. 2026-09-18 22:48 UTCGHSA enrichment
  18. 2026-09-18 19:28 UTCEPSS rescore
  19. 2026-09-17 23:58 UTCEG score recompute
  20. 2026-09-17 23:58 UTCGHSA enrichment
  21. 2026-09-17 19:32 UTCEPSS rescore
  22. 2026-09-16 23:55 UTCEG score recompute
  23. 2026-09-16 23:55 UTCGHSA enrichment
  24. 2026-09-16 14:09 UTCEPSS rescore
  25. 2026-09-16 05:15 UTCEPSS rescore
Show 47 more
  1. 2026-09-16 01:04 UTCEG score recompute
  2. 2026-09-16 01:04 UTCGHSA enrichment
  3. 2026-09-15 03:12 UTCEPSS rescore
  4. 2026-09-15 03:12 UTCEPSS rescore
  5. 2026-09-15 02:13 UTCGHSA enrichment
  6. 2026-09-14 03:22 UTCEG score recompute
  7. 2026-09-14 03:22 UTCGHSA enrichment
  8. 2026-09-13 04:32 UTCEG score recompute
  9. 2026-09-13 04:32 UTCGHSA enrichment
  10. 2026-09-12 05:41 UTCEG score recompute
  11. 2026-09-12 05:41 UTCGHSA enrichment
  12. 2026-09-11 14:53 UTCEPSS rescore
  13. 2026-09-11 14:53 UTCEPSS rescore
  14. 2026-09-11 06:50 UTCEG score recompute
  15. 2026-09-11 06:50 UTCGHSA enrichment
  16. 2026-09-10 07:59 UTCGHSA enrichment
  17. 2026-09-09 09:08 UTCEG score recompute
  18. 2026-09-09 09:08 UTCGHSA enrichment
  19. 2026-09-08 22:01 UTCEPSS rescore
  20. 2026-09-08 10:17 UTCEG score recompute
  21. 2026-09-08 10:16 UTCGHSA enrichment
  22. 2026-09-07 11:23 UTCEG score recompute
  23. 2026-09-07 11:23 UTCGHSA enrichment
  24. 2026-09-06 13:48 UTCEPSS rescore
  25. 2026-09-06 12:30 UTCEG score recompute
  26. 2026-09-06 12:30 UTCGHSA enrichment
  27. 2026-09-05 15:31 UTCEPSS rescore
  28. 2026-09-05 13:39 UTCGHSA enrichment
  29. 2026-09-04 14:49 UTCEG score recompute
  30. 2026-09-04 14:49 UTCGHSA enrichment
  31. 2026-09-04 05:07 UTCEPSS rescore
  32. 2026-09-03 15:55 UTCGHSA enrichment
  33. 2026-09-02 16:58 UTCEG score recompute
  34. 2026-09-02 16:58 UTCGHSA enrichment
  35. 2026-09-02 14:12 UTCEPSS rescore
  36. 2026-09-01 22:20 UTCGHSA enrichment
  37. 2026-09-01 21:53 UTCGHSA enrichment
  38. 2026-09-01 21:43 UTCGHSA enrichment
  39. 2026-09-01 21:09 UTCEG score recompute
  40. 2026-09-01 21:09 UTCGHSA enrichment
  41. 2026-09-01 16:27 UTCGHSA enrichment
  42. 2026-09-01 15:45 UTCEG score recompute▲ 5.40
  43. 2026-09-01 15:44 UTCGHSA enrichment
  44. 2026-09-01 15:42 UTCMITRE cvelistV5CVSS v3 → 5.4 · severity → MEDIUM
  45. 2026-09-01 13:35 UTCNVD update
  46. 2026-09-01 12:45 UTCEG score recompute
  47. 2026-09-01 12:41 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-84118?
CVE-2026-84118 is a medium vulnerability published on September 1, 2026. Use-after-free in the JavaScript: GC component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.
When was CVE-2026-84118 disclosed?
CVE-2026-84118 was first published in the National Vulnerability Database on September 1, 2026, with the most recent update on September 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-84118 actively exploited?
CVE-2026-84118 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 81.2% of all scored CVEs.
What is the CVSS score of CVE-2026-84118?
CVE-2026-84118 has a CVSS v3.1 base score of 5.4 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-84118?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-84118, 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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