CVE-2026-92021

HIGHPre-NVD 8.88.8—
EchelonGraph scoreHIGH confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-09-15. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — Patch released this week
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.8Exploit: None knownExposed: 0

A fix is available — apply it.

Use-after-free in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox ESR 140.16 and Thunderbird 140.16.

CVSS v3
8.8
EG Score
8.8(high)
EG Risk
40(Track)
EG Risk 40/100SSVC: 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
Severity88% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
20%
KEV
Not listed

Published

September 15, 2026

Last Modified

September 20, 2026

Advisory Details (3)

Auto-updated Sep 20, 2026
No patch confirmed yet.
generic

Security Vulnerabilities fixed in Thunderbird 140.16 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-95/
generic

Security Vulnerabilities fixed in Firefox ESR 140.16 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-92/
generic

Access Denied

https://bugzilla.mozilla.org/show_bug.cgi?id=2067208

Vendor Advisories for CVE-2026-92021(3)

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
redhatthunderbird-0:140.16.0-1.el9_82026-09-24redhat
redhatfirefox-0:140.16.0-1.el10_22026-09-21redhat
redhatfirefox-0:140.16.0-1.el9_82026-09-21redhat

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.

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 33× in last 7d / 44× 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. 2026-09-25 02:19 UTCVendor advisory
  2. 2026-09-25 02:19 UTCGHSA enrichment
  3. 2026-09-24 14:16 UTCEG score recompute
  4. 2026-09-24 14:16 UTCVendor advisory
  5. 2026-09-24 14:16 UTCGHSA enrichment
  6. 2026-09-24 14:04 UTCEPSS rescore
  7. 2026-09-24 01:58 UTCEG score recompute
  8. 2026-09-24 01:58 UTCVendor advisory
  9. 2026-09-24 01:58 UTCGHSA enrichment
  10. 2026-09-23 17:54 UTCEPSS rescore
  11. 2026-09-23 13:56 UTCVendor advisory
  12. 2026-09-23 13:55 UTCGHSA enrichment
  13. 2026-09-23 01:53 UTCEG score recompute
  14. 2026-09-23 01:53 UTCVendor advisory
  15. 2026-09-23 01:53 UTCGHSA enrichment
  16. 2026-09-22 16:01 UTCEPSS rescore
  17. 2026-09-22 13:50 UTCVendor advisory
  18. 2026-09-22 13:50 UTCGHSA enrichment
  19. 2026-09-22 01:48 UTCEG score recompute
  20. 2026-09-22 01:48 UTCVendor advisory
  21. 2026-09-22 01:48 UTCGHSA enrichment
  22. 2026-09-21 21:09 UTCEPSS rescore
  23. 2026-09-21 13:45 UTCGHSA enrichment
  24. 2026-09-21 01:37 UTCEG score recompute
  25. 2026-09-21 01:37 UTCGHSA enrichment
Show 19 more
  1. 2026-09-20 20:16 UTCEPSS rescore
  2. 2026-09-20 13:34 UTCEG score recompute
  3. 2026-09-20 13:34 UTCGHSA enrichment
  4. 2026-09-20 01:32 UTCGHSA enrichment
  5. 2026-09-20 01:01 UTCEG score recompute▲ 8.80
  6. 2026-09-20 01:01 UTCGHSA enrichment
  7. 2026-09-20 01:00 UTCMITRE cvelistV5CVSS v3 → 8.8 · severity → HIGH
  8. 2026-09-18 19:28 UTCEPSS rescore
  9. 2026-09-17 19:32 UTCEPSS rescore
  10. 2026-09-16 19:58 UTCEG score recompute
  11. 2026-09-16 19:58 UTCGHSA enrichment
  12. 2026-09-16 14:09 UTCEPSS rescore
  13. 2026-09-15 20:45 UTCGHSA enrichment
  14. 2026-09-15 20:32 UTCNVD update
  15. 2026-09-15 19:49 UTCGHSA enrichment
  16. 2026-09-15 19:47 UTCMITRE cvelistV5
  17. 2026-09-15 13:30 UTCNVD update
  18. 2026-09-15 12:39 UTCEG score recompute
  19. 2026-09-15 12:37 UTCMITRE cvelistV5first tracked

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-92021?
CVE-2026-92021 is a high vulnerability published on September 15, 2026. Use-after-free in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox ESR 140.16 and Thunderbird 140.16.
When was CVE-2026-92021 disclosed?
CVE-2026-92021 was first published in the National Vulnerability Database on September 15, 2026, with the most recent update on September 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-92021 actively exploited?
CVE-2026-92021 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 79.7% of all scored CVEs.
What is the CVSS score of CVE-2026-92021?
CVE-2026-92021 has a CVSS v3.1 base score of 8.8 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-92021?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-92021, 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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