CVE-2026-84639
criticalpriority · track · 0EPSS 0.003 · 25 %ileDEUSEPSS · scored 2026-10-27
Triggering an error condition in certain MIME bodies would cause uninitialized memory to be used. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, 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⚠ sources disagree · high–critical · 8.3–9.1
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (25)
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 (4) nvd
External citations — patches, advisories, analysis.
- https://bugzilla.mozilla.org/show_bug.cgi?id=2061087Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-86/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-87/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-88/Vendor Advisory
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