---
cve: "CVE-2026-8959"
severity: "CRITICAL"
cvss: 9.6
epss: "42%"
vendor: "Generic Security"
kev: false
exploited: false
published: "2026-05-19 14:16:52"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-07T07:26:11+02:00"
---

# CVE-2026-8959

> 9.6 CRITICAL

## Beschreibung

Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

## CVSS-Vektor

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

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

## Referenzen

- <https://bugzilla.mozilla.org/show_bug.cgi?id=2034754>
- <https://www.mozilla.org/security/advisories/mfsa2026-46/>
- <https://www.mozilla.org/security/advisories/mfsa2026-48/>
- <https://www.mozilla.org/security/advisories/mfsa2026-50/>
- <https://www.mozilla.org/security/advisories/mfsa2026-51/>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-8959) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_