CVE-2026-16371

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 — Patch released 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

A fix is available — apply it.

Privilege escalation in the DOM: Navigation component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

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
20%
KEV
Not listed

Published

July 21, 2026

Last Modified

July 24, 2026

Advisory Details (5)

Auto-updated Jul 24, 2026
⚠️ Active exploitation confirmed. No patch confirmed yet.
generic🔴 Active Exploitation

Security Vulnerabilities fixed in Thunderbird 140.13 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-72/
generic

Security Vulnerabilities fixed in Thunderbird 153 — Mozilla

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

Security Vulnerabilities fixed in Firefox ESR 140.13 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-70/
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=2008369

Vendor Advisories for CVE-2026-16371(2)

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

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatfirefox-0:140.13.0-1.el8_102026-07-28redhat
redhatfirefox-0:140.13.0-1.el10_22026-07-28redhat

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 44× in last 7d / 49× 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. 2026-07-29 10:44 UTCVendor advisory
  2. 2026-07-29 10:44 UTCGHSA enrichment
  3. 2026-07-29 06:53 UTCVendor advisory
  4. 2026-07-29 06:53 UTCGHSA enrichment
  5. 2026-07-29 03:01 UTCVendor advisory
  6. 2026-07-29 03:01 UTCGHSA enrichment
  7. 2026-07-28 23:11 UTCGHSA enrichment
  8. 2026-07-28 19:01 UTCEG score recompute
  9. 2026-07-28 19:01 UTCGHSA enrichment
  10. 2026-07-28 15:07 UTCGHSA enrichment
  11. 2026-07-28 11:14 UTCGHSA enrichment
  12. 2026-07-28 07:17 UTCGHSA enrichment
  13. 2026-07-28 03:22 UTCGHSA enrichment
  14. 2026-07-27 23:32 UTCGHSA enrichment
  15. 2026-07-27 19:10 UTCGHSA enrichment
  16. 2026-07-27 15:13 UTCEG score recompute
  17. 2026-07-27 15:13 UTCGHSA enrichment
  18. 2026-07-27 14:13 UTCEPSS rescore
  19. 2026-07-27 09:51 UTCGHSA enrichment
  20. 2026-07-27 06:02 UTCGHSA enrichment
  21. 2026-07-27 02:06 UTCGHSA enrichment
  22. 2026-07-26 22:16 UTCGHSA enrichment
  23. 2026-07-26 18:26 UTCEG score recompute
  24. 2026-07-26 18:26 UTCGHSA enrichment
  25. 2026-07-26 14:54 UTCEPSS rescore
Show 24 more
  1. 2026-07-26 14:54 UTCEPSS rescore
  2. 2026-07-26 14:33 UTCGHSA enrichment
  3. 2026-07-26 10:42 UTCEG score recompute
  4. 2026-07-26 10:42 UTCGHSA enrichment
  5. 2026-07-26 04:23 UTCEG score recompute
  6. 2026-07-26 04:22 UTCGHSA enrichment
  7. 2026-07-25 14:17 UTCEPSS rescore
  8. 2026-07-25 14:17 UTCEPSS rescore
  9. 2026-07-24 20:41 UTCMITRE cvelistV5CVSS v3 → 8.8 · severity → HIGH
  10. 2026-07-24 14:17 UTCEPSS rescore
  11. 2026-07-23 14:18 UTCEPSS rescore
  12. 2026-07-23 14:18 UTCEPSS rescore
  13. 2026-07-23 03:05 UTCEG score recompute
  14. 2026-07-22 23:16 UTCEG score recompute
  15. 2026-07-22 23:15 UTCGHSA enrichment
  16. 2026-07-22 16:02 UTCEG score recompute▲ 9.80
  17. 2026-07-22 16:01 UTCGHSA enrichment
  18. 2026-07-22 16:00 UTCMITRE cvelistV5CVSS v3 → 9.8 · severity → CRITICAL
  19. 2026-07-22 14:08 UTCEPSS rescore
  20. 2026-07-21 19:19 UTCNVD update
  21. 2026-07-21 18:43 UTCMITRE cvelistV5
  22. 2026-07-21 14:51 UTCNVD update
  23. 2026-07-21 12:50 UTCEG score recompute
  24. 2026-07-21 12:48 UTCMITRE cvelistV5first tracked

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-16371?
CVE-2026-16371 is a critical vulnerability published on July 21, 2026. Privilege escalation in the DOM: Navigation component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
When was CVE-2026-16371 disclosed?
CVE-2026-16371 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-2026-16371 actively exploited?
CVE-2026-16371 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 80.0% of all scored CVEs.
What is the CVSS score of CVE-2026-16371?
CVE-2026-16371 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-2026-16371?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-16371, 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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