Sandbox Escape and Site Isolation Issue in Firefox by Mozilla

CVE-2026-109705

What is CVE-2026-109705?

A sandbox escape vulnerability has been identified in the Networking component of Firefox, which arises from incorrect boundary conditions and a use-after-free error. This flaw compromises site isolation by potentially allowing malicious entities to execute arbitrary actions outside of the intended security constraints. Mozilla has addressed this issue in the releases of Firefox 158 and Firefox ESR 153.5. Users are encouraged to update their browsers to mitigate the risks associated with this vulnerability.

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