Mozilla Firefox and Thunderbird Denial-of-Service Vulnerability

Added to KEV
2022-03-28
Federal due date
2022-04-18
Vendor
Mozilla
Product
Firefox and Thunderbird
EPSS
97.7th percentile (score 0.471, as of 2026-06-08)
NVD CVSS v3.1
Ransomware use
Unknown
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2013-1690

CISA short description

Mozilla Firefox and Thunderbird do not properly handle onreadystatechange events in conjunction with page reloading, which allows remote attackers to cause a denial-of-service (DoS) or possibly execute malicious code via a crafted web site.

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.