Executive brief
Firefox's DOM Navigation component contains a privilege escalation vulnerability that could allow an attacker to gain elevated access within the browser sandbox. Successful exploitation could enable an attacker to bypass security restrictions and access sensitive user data or perform unauthorized actions with the privileges of the Firefox process.
Technical details
This is a privilege escalation vulnerability in the DOM: Navigation component of Firefox. The vulnerability allows an attacker to bypass sandbox restrictions and gain elevated privileges. The attack requires network access to deliver malicious content to a victim's browser; no prior authentication is required, but the attacker must convince or trick the user to visit a malicious webpage or interact with crafted content. Successful exploitation could allow arbitrary code execution or access to protected browser APIs. The vulnerability has been patched in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
Affected products
- Mozilla Firefox before 154
- Mozilla Firefox ESR 115.x before 115.39, 140.x before 140.14, 153.x before 153.1
- Mozilla Thunderbird before 154, 140.x before 140.14, 153.x before 153.1
Timeline
- 2026-08-18: disclosed
- 2026-08-18: patched: Fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1