CVE-2009-1833: Mozilla Firefox

High severity, CVSS 9.3. EPSS: 9.2% chance of exploitation in the next 30 days.

The JavaScript engine in Mozilla Firefox before 3.0.11, Thunderbird before 2.0.0.22, and SeaMonkey before 1.1.17 allows remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via vectors related to (1) js_LeaveSharpObject, (2) ParseXMLSource, and (3) a certain assertion in jsinterp.c; and other vectors.

Affected products

• Mozilla Firefox: up to and including 3.0.10; version 0.1 only; version 0.2 only; version 0.3 only; version 0.4 only; version 0.5 only; …
• Mozilla Seamonkey: up to and including 1.1.16; version 1.0 only; version 1.0.1 only; version 1.0.3 only; version 1.0.4 only; version 1.0.6 only; …
• Mozilla Thunderbird: up to and including 2.0.0.19; version 0.1 only; version 0.2 only; version 0.3 only; version 0.4 only; version 0.5 only; …

Published 2009-06-12. Last modified 2026-06-16.