CVE-2026-100803 | Mozilla Firefox up to 115.41/140.16/153.3/156 WebExtensions cross-domain policy

September 29, 2026 Yanac

A vulnerability classified as problematic has been found in Mozilla Firefox up to 115.41/140.16/153.3/156. This affects an unknown function of the component WebExtensions. Performing a manipulation results in permissive cross-domain policy with untrusted domains.

This vulnerability is known as CVE-2026-100803. Remote exploitation of the attack is possible. No exploit is available.

It is recommended to upgrade the affected component.VulDB Recent EntriesRead More