{"id":"CVE-2026-109705","published":"2026-10-13T13:17:20.587","lastModified":"2026-10-13T19:18:33.667","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.","cvssScore":9.6,"cvssSeverity":"CRITICAL","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H","cwes":["CWE-416"],"vendors":[],"products":[],"references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=2040905","tags":[]},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-106/","tags":[]},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-108/","tags":[]},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-109/","tags":[]},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-110/","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":{"summary":"This vulnerability is a use-after-free flaw in Firefox's networking component that allows attackers to escape the browser sandbox and potentially execute arbitrary code with high privileges. The issue occurs due to incorrect boundary conditions in site isolation, making it particularly dangerous for web-based attacks.","exploitability":"Exploitation requires a user visiting a malicious website with specific JavaScript payloads, but is relatively straightforward once the user is on the page since it leverages well-understood use-after-free patterns.","blast_radius":"If exploited, this vulnerability could allow attackers to escape browser sandboxing and execute arbitrary code on the victim's system with full user privileges, potentially leading to complete system compromise.","remediation":"Upgrade to Firefox 158 or Thunderbird 158 immediately, as these versions contain the fix for this critical sandbox escape vulnerability.","detection":"No reliable host or network indicator is derivable from the published description.","tags":["sandbox-escape","use-after-free","browser"],"model":"garnet-coder","analyzedAt":"2026-10-15T08:53:24.063Z"}}