Mozilla Firefox and Thunderbird Sandbox Escape Vulnerability

Added to KEV
2022-05-23
Federal due date
2022-06-13
Vendor
Mozilla
Product
Firefox and Thunderbird
EPSS
98.6th percentile (score 0.688, as of 2026-06-08)
NVD CVSS v3.1
Ransomware use
Unknown
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2019-11708

CISA short description

Mozilla Firefox and Thunderbird contain a sandbox escape vulnerability that could result in remote code execution.

Required action

Apply updates per vendor instructions.

EPSS percentile is the FIRST.org exploit-probability ranking as of the date noted above; it moves daily. CVSS reflects NVD's analysis at time of publication.