CVE-2026-2770 is a use-after-free vulnerability in the DOM: Bindings (WebIDL) component of Mozilla Firefox. Use-after-free flaws occur when a program continues to use a pointer after the memory it points to has been freed, potentially leading to memory corruption. This vulnerability was addressed and fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8. The Mozilla advisories confirm the high impact of this vulnerability and provide patches in the stated versions. No known exploits in the wild have been reported at the time of disclosure.

The vulnerability can lead to high impact on confidentiality, integrity, and availability, as indicated by the CVSS 3.1 score of 8.8 (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H). Successful exploitation could allow an attacker to execute arbitrary code or cause a denial of service by leveraging memory corruption through the use-after-free condition in the DOM Bindings component.

Mozilla has released official fixes for this vulnerability in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8. Users and administrators should update to these versions or later to remediate the vulnerability. No additional mitigation steps are required beyond applying the official patches.