---
cve: "CVE-2026-84639"
severity: "CRITICAL"
cvss: 9.1
epss: "56.7%"
vendor: "Generic Security"
kev: false
exploited: false
published: "2026-09-01 22:17:19"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-04T03:06:48+02:00"
---

# CVE-2026-84639

> 9.1 CRITICAL

## Beschreibung

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-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Keine | good |
| A Verfügbarkeit | Hoch | bad |

## Referenzen

- <https://bugzilla.mozilla.org/show_bug.cgi?id=2061087>
- <https://www.mozilla.org/security/advisories/mfsa2026-86/>
- <https://www.mozilla.org/security/advisories/mfsa2026-87/>
- <https://www.mozilla.org/security/advisories/mfsa2026-88/>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-84639) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_