CVE-2010-1585: Mozilla Firefox

High severity, CVSS 9.3. EPSS: 4.5% chance of exploitation in the next 30 days.

The nsIScriptableUnescapeHTML.parseFragment method in the ParanoidFragmentSink protection mechanism in Mozilla Firefox before 3.5.17 and 3.6.x before 3.6.14, Thunderbird before 3.1.8, and SeaMonkey before 2.0.12 does not properly sanitize HTML in a chrome document, which makes it easier for remote attackers to execute arbitrary JavaScript with chrome privileges via a javascript: URI in input to an extension, as demonstrated by a javascript:alert sequence in (1) the HREF attribute of an A element or (2) the ACTION attribute of a FORM element.

Affected products

• Mozilla Firefox: version 3.6 only; version 3.6.2 only; version 3.6.3 only; version 3.6.4 only; version 3.6.6 only; version 3.6.7 only; …
• Mozilla Seamonkey: up to and including 2.0.11; version 1.0 only; version 1.0.1 only; version 1.0.2 only; version 1.0.3 only; version 1.0.4 only; …
• Mozilla Thunderbird: up to and including 3.1.7; version 0.1 only; version 0.2 only; version 0.3 only; version 0.4 only; version 0.5 only; …

Published 2010-04-28. Last modified 2026-06-16.