CVE-2026-84118
Use-after-free in the JavaScript: GC component
MEDIUM 5.4EPSS 0.3%
Use-after-free in the JavaScript: GC component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.
- Affected
- Mozilla · Firefox · Thunderbird
- CVSS v3.1 CNA
- 5.4 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N - EPSS
- 0.29% chance of exploitation in the next 30 days, 20th percentile
- Published
- 2026-09-01
Proof-of-concept exploits (1)
- SneakyNachos/CVE-2026-84118-who-labeled-the-crit-as-a-high1★ · 2026-09-08
Security advisories
- https://www.mozilla.org/security/advisories/mfsa2026-82
- https://www.mozilla.org/security/advisories/mfsa2026-85
- https://www.mozilla.org/security/advisories/mfsa2026-86
- https://www.mozilla.org/security/advisories/mfsa2026-88