CVE-2026-100776
Use-after-free in the JavaScript: WebAssembly component
- Risk score
- 62/100
- CVSS
- 8.8 v3.1
- Exploit chance (30 days)
- 0.3%
- Published
- 29 Sep 2026
Open in the live forecast Today's forecast
What to know
- What it is
- Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.
- Affected
- Firefox
- Fix
- Apply the vendor's security update; see the linked advisory.
- Exploitation
- No known exploitation
Why it is Amber
- CVSS 8.8 high
- Remotely exploitable without logging in
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2068374
- https://www.mozilla.org/security/advisories/mfsa2026-100/
- https://www.mozilla.org/security/advisories/mfsa2026-101/
- https://www.mozilla.org/security/advisories/mfsa2026-102/
- https://www.mozilla.org/security/advisories/mfsa2026-103/
- https://www.mozilla.org/security/advisories/mfsa2026-97/
- https://www.mozilla.org/security/advisories/mfsa2026-99/
Original description
Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.
Last activity 29 Sep 2026. Patch Forecast updates every hour.