CVE-2019-11708: Mozilla Firefox and Thunderbird Sandbox Escape Vulnerability

Critical severity, CVSS 10.0. Actively exploited: in CISA KEV since 2022-05-23. EPSS: 55.9% chance of exploitation in the next 30 days.

Insufficient vetting of parameters passed with the Prompt:Open IPC message between child and parent processes can result in the non-sandboxed parent process opening web content chosen by a compromised child process. When combined with additional vulnerabilities this could result in executing arbitrary code on the user's computer. This vulnerability affects Firefox ESR < 60.7.2, Firefox < 67.0.4, and Thunderbird < 60.7.2.

Affected products

• Mozilla Firefox: before 60.7.2 (fixed in 60.7.2); before 67.0.4 (fixed in 67.0.4)
• Mozilla Thunderbird: before 60.7.2 (fixed in 60.7.2)

Published 2019-07-23. Last modified 2026-06-17.