CVE-2026-16365

CRITICALPre-NVD 8.89.8▲
EchelonGraph scoreHIGH confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-07-21. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 8.8; sources differ by 1.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 4 sources updated this week
9.8EG
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

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

Privilege escalation in the DOM: Workers component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

CVSS v3
8.8
EG Score
9.8(high)
EG Risk
44(Track)
EG Risk 44/100SSVC: 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
Severity98% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
19%
KEV
Not listed

Published

July 21, 2026

Last Modified

July 24, 2026

Advisory Details (3)

Auto-updated Jul 24, 2026
No patch confirmed yet.
generic

Security Vulnerabilities fixed in Thunderbird 153 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-71/
generic

Security Vulnerabilities fixed in Firefox 153 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-68/
generic

Access Denied

https://bugzilla.mozilla.org/show_bug.cgi?id=2049149

Vendor Advisories for CVE-2026-16365(1)

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

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 43× in last 7d / 55× 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. 2026-07-30 18:55 UTCEG score recompute
  2. 2026-07-30 18:55 UTCGHSA enrichment
  3. 2026-07-30 14:42 UTCGHSA enrichment
  4. 2026-07-30 10:23 UTCEG score recompute
  5. 2026-07-30 10:23 UTCGHSA enrichment
  6. 2026-07-30 06:16 UTCGHSA enrichment
  7. 2026-07-30 02:06 UTCEG score recompute
  8. 2026-07-30 02:06 UTCGHSA enrichment
  9. 2026-07-30 01:30 UTCEPSS rescore
  10. 2026-07-29 21:58 UTCGHSA enrichment
  11. 2026-07-29 17:48 UTCGHSA enrichment
  12. 2026-07-29 13:41 UTCGHSA enrichment
  13. 2026-07-29 09:34 UTCGHSA enrichment
  14. 2026-07-29 05:26 UTCGHSA enrichment
  15. 2026-07-29 01:19 UTCGHSA enrichment
  16. 2026-07-28 21:11 UTCGHSA enrichment
  17. 2026-07-28 17:03 UTCEG score recompute
  18. 2026-07-28 17:03 UTCGHSA enrichment
  19. 2026-07-28 12:47 UTCGHSA enrichment
  20. 2026-07-28 08:39 UTCGHSA enrichment
  21. 2026-07-28 04:31 UTCGHSA enrichment
  22. 2026-07-28 00:22 UTCGHSA enrichment
  23. 2026-07-27 19:53 UTCGHSA enrichment
  24. 2026-07-27 15:43 UTCEG score recompute
  25. 2026-07-27 15:43 UTCGHSA enrichment
Show 30 more
  1. 2026-07-27 14:13 UTCEPSS rescore
  2. 2026-07-27 11:36 UTCGHSA enrichment
  3. 2026-07-27 07:26 UTCGHSA enrichment
  4. 2026-07-27 03:17 UTCGHSA enrichment
  5. 2026-07-26 23:07 UTCGHSA enrichment
  6. 2026-07-26 19:00 UTCEG score recompute
  7. 2026-07-26 19:00 UTCGHSA enrichment
  8. 2026-07-26 14:54 UTCEPSS rescore
  9. 2026-07-26 14:54 UTCEPSS rescore
  10. 2026-07-26 14:52 UTCGHSA enrichment
  11. 2026-07-26 10:42 UTCEG score recompute
  12. 2026-07-26 10:42 UTCGHSA enrichment
  13. 2026-07-26 04:23 UTCEG score recompute
  14. 2026-07-26 04:23 UTCGHSA enrichment
  15. 2026-07-25 14:17 UTCEPSS rescore
  16. 2026-07-25 14:17 UTCEPSS rescore
  17. 2026-07-24 20:41 UTCMITRE cvelistV5CVSS v3 → 8.8 · severity → HIGH
  18. 2026-07-24 14:17 UTCEPSS rescore
  19. 2026-07-23 14:18 UTCEPSS rescore
  20. 2026-07-23 14:18 UTCEPSS rescore
  21. 2026-07-23 03:05 UTCEG score recompute
  22. 2026-07-22 23:17 UTCEG score recompute
  23. 2026-07-22 23:16 UTCGHSA enrichment
  24. 2026-07-22 16:03 UTCEG score recompute▲ 9.80
  25. 2026-07-22 16:03 UTCGHSA enrichment
  26. 2026-07-22 16:00 UTCMITRE cvelistV5CVSS v3 → 9.8 · severity → CRITICAL
  27. 2026-07-22 14:08 UTCEPSS rescore
  28. 2026-07-21 14:51 UTCNVD update
  29. 2026-07-21 12:50 UTCEG score recompute
  30. 2026-07-21 12:48 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-16365?
CVE-2026-16365 is a critical vulnerability published on July 21, 2026. Privilege escalation in the DOM: Workers component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.
When was CVE-2026-16365 disclosed?
CVE-2026-16365 was first published in the National Vulnerability Database on July 21, 2026, with the most recent update on July 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-16365 actively exploited?
CVE-2026-16365 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 81.1% of all scored CVEs.
What is the CVSS score of CVE-2026-16365?
CVE-2026-16365 has a CVSS v3.1 base score of 8.8 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.8.
How do I remediate CVE-2026-16365?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-16365, 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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