CVE-2026-84118
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.
- Published Sep 1, 2026
- CVSS 5.4 medium
- 0.3% chance of exploitation in the next 30 days (EPSS)
- A fix is available