Is CVE-2026-109705 being exploited?

No public exploit is currently tracked.

How severe is CVE-2026-109705?

CVE-2026-109705 has a CVSS v3 severity of CRITICAL (9.6).

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CVE-2026-109705

Description

Sandbox escape, site isolation issue due to incorrect boundary conditions, use-after-free in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.