---
cve: "CVE-2026-74936"
severity: "CRITICAL"
cvss: 9.8
epss: "0.6%"
vendor: "Generic Security"
kev: false
exploited: false
published: "2026-08-18 13:17:29"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-10-23T20:46:07+02:00"
---

# CVE-2026-74936

> 9.8 CRITICAL

## Beschreibung

Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

## CNA-Record (Kanon, cvelistV5)

- CNA: **mozilla**
- State: PUBLISHED
- Stand: 2026-08-21 20:11:20

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **none**
  - Automatable: **yes**
  - Technical Impact: **total**

## 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 |

## Schwachstellen-Klasse

- **CWE-416** — Use After Free
  The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

## BSI-Hinweise (deutsch)

- [Mozilla Firefox, Firefox ESR und Thunderbird: Mehrere Schwachstellen](https://wid.cert-bund.de/portal/wid/sicherheitshinweis/WID-SEC-W-2026-2911) — _BSI-Einstufung: hoch_
  Ein Angreifer kann mehrere Schwachstellen in Mozilla Firefox, Firefox ESR und Thunderbird ausnutzen, um seine Privilegien zu erhöhen, Sicherheitsmaßnahmen zu umgehen, vertrauliche Informationen offenzulegen, Spoofing- oder Clickjacking-Angriffe durchzuführen oder Denial-of-Service-Zustände herbeizuführen.

## Referenzen

- <https://bugzilla.mozilla.org/show_bug.cgi?id=2052688>
- <https://www.mozilla.org/security/advisories/mfsa2026-74/>
- <https://www.mozilla.org/security/advisories/mfsa2026-76/>
- <https://www.mozilla.org/security/advisories/mfsa2026-77/>
- <https://www.mozilla.org/security/advisories/mfsa2026-78/>
- <https://www.mozilla.org/security/advisories/mfsa2026-79/>
- <https://www.mozilla.org/security/advisories/mfsa2026-80/>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2026-74936/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_