CVE-2026-84118
mediumpriority · track · 10EPSS 0.003 · 21 %ileexploit · PoCDEUSEPSS · scored 2026-10-27
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
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
exploits (1)
Public proof-of-concept and weaponised exploit code.
affected products (26)
Products and version ranges known to be affected.
advisories (1)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-3132Mozilla Firefox und Thunderbird: Mehrere SchwachstellenDeutsch2026-09-01csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Mozilla Firefox und Thunderbird ausnutzen, um Berechtigungen zu erweitern, Sicherheitsmaßnahmen zu umgehen, sensible Informationen offenzulegen, Daten zu manipulieren, Spoofing-Angriffe durchzuführen, möglicherweise durch Speicherbeschädigungen beliebigen Code auszuführen oder Denial-of-Service-Zustände herbeizuführen.
sources
Which sources assert this record, and when.
references (5) nvd
External citations — patches, advisories, analysis.
- https://bugzilla.mozilla.org/show_bug.cgi?id=2057457Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-82/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-85/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-86/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-88/Vendor Advisory
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