Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.
CVE-2026-100785
Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-09-29. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 8.8; sources differ by 0.0.
- High severity, but no confirmed exploitation yet
No fix is confirmed yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for the fix.
- CVSS v3
- 8.8
- EG Score
- 8.8HIGHhigh confidence
- EG Risk
- 40EG Risk 40/100CISA SSVC
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 computedSeverity88% × 45%Exploitation0% × 40%Automatability0% × 15%CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix. - EPSS PROB
- 0.3%
- EPSS %ILE
- 25th
- KEV
- Not listed
CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).
No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table
Published
September 29, 2026
Last Modified
September 30, 2026
Advisory Details (5)
Auto-updated Sep 29, 2026Security Vulnerabilities fixed in Firefox ESR 140.17 — Mozilla
https://www.mozilla.org/security/advisories/mfsa2026-99/Security Vulnerabilities fixed in Firefox ESR 115.42 — Mozilla
https://www.mozilla.org/security/advisories/mfsa2026-98/Security Vulnerabilities fixed in Firefox 157 — Mozilla
https://www.mozilla.org/security/advisories/mfsa2026-97/Security Vulnerabilities fixed in Firefox ESR 153.4 — Mozilla
https://www.mozilla.org/security/advisories/mfsa2026-100/Vendor Advisories for CVE-2026-100785(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 25× in last 7d / 25× 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.
- 2026-10-04 04:10 UTCGHSA enrichment
- 2026-10-03 16:33 UTCEG score recompute
- 2026-10-03 16:33 UTCGHSA enrichment
- 2026-10-03 14:25 UTCEPSS rescore
- 2026-10-03 04:57 UTCGHSA enrichment
- 2026-10-02 17:19 UTCEG score recompute
- 2026-10-02 17:19 UTCGHSA enrichment
- 2026-10-02 05:39 UTCEG score recompute
- 2026-10-02 05:39 UTCGHSA enrichment
- 2026-10-01 19:49 UTCEPSS rescore
- 2026-10-01 17:59 UTCGHSA enrichment
- 2026-10-01 06:17 UTCGHSA enrichment
- 2026-09-30 18:40 UTCGHSA enrichment
- 2026-09-30 17:22 UTCEG score recompute
- 2026-09-30 17:22 UTCGHSA enrichment
- 2026-09-30 15:02 UTCEPSS rescore
- 2026-09-30 08:47 UTCGHSA enrichment
- 2026-09-30 04:07 UTCGHSA enrichment
- 2026-09-29 22:06 UTCEG score recompute
- 2026-09-29 22:06 UTCGHSA enrichment
- 2026-09-29 14:59 UTCEG score recompute▲ 8.80
- 2026-09-29 14:58 UTCMITRE cvelistV5CVSS v3 → 8.8 · severity → HIGH
- 2026-09-29 13:35 UTCNVD update
- 2026-09-29 12:50 UTCEG score recompute
- 2026-09-29 12:48 UTCMITRE cvelistV5first tracked
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Frequently asked(5)
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Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-100785
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