---
cve: "CVE-2026-84142"
severity: "CRITICAL"
cvss: 9.8
epss: "57.3%"
vendor: "Generic Security"
kev: false
exploited: false
published: "2026-09-01 13:20:08"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-07T12:43:49+02:00"
---

# CVE-2026-84142

> 9.8 CRITICAL

## Beschreibung

Internally found bugs present in Thunderbird 154. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 155 and Thunderbird 155.

## CVSS-Vektor

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

## Referenzen

- <https://bugzilla.mozilla.org/buglist.cgi?bug_id=2029421%2C2040889%2C2045313%2C2045435%2C2053578%2C2058621%2C2058626>
- <https://bugzilla.mozilla.org/buglist.cgi?bug_id=2048796%2C2053150%2C2057356>
- <https://www.mozilla.org/security/advisories/mfsa2026-82/>
- <https://www.mozilla.org/security/advisories/mfsa2026-86/>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-84142) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_