CVE-2026-12291High· 8.8▾ TwilightUse-after-free in the Networking: HTTP component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 48.4 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 7.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
Last analysed / modified upstream
0.4%
Use-after-free in the Networking: HTTP component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.
firefox < 115.37.0firefox < 152.0.0firefox >= 128.0, < 140.12.0thunderbird < 140.12.0thunderbird < 152.0.0Upgrade past the affected range:
firefox 140.12.0thunderbird 152.0.0Connected by shared product, vendor, weakness, or advisory.
CVE-2026-12329Medium· 5.3Memory safety bug fixed in Thunderbird ESR 140.12
CVE-2026-12328High· 8.1Memory safety bugs present in Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird ESR 140.11, Firefox 151 and Thunderbird 151
CVE-2026-12298Medium· 5.4Memory safety bug fixed in Firefox 152
CVE-2026-12299Medium· 5.4JIT miscompilation in the DOM: Core & HTML component
CVE-2026-12297Critical· 9.6Sandbox escape due to incorrect boundary conditions in the Networking component
CVE-2026-12296Critical· 9.6Sandbox escape in the Security: Process Sandboxing component