CVE-2011-3000: Mozilla Firefox

Medium severity, CVSS 4.3. EPSS: 2% chance of exploitation in the next 30 days.

Mozilla Firefox before 3.6.23 and 4.x through 6, Thunderbird before 7.0, and SeaMonkey before 2.4 do not properly handle HTTP responses that contain multiple Location, Content-Length, or Content-Disposition headers, which makes it easier for remote attackers to conduct HTTP response splitting attacks via crafted header values.

Affected products

• Mozilla Firefox: up to and including 3.6.22; version 3.6 only; version 3.6.2 only; version 3.6.3 only; version 3.6.4 only; version 3.6.6 only; …
• Mozilla Seamonkey: up to and including 2.3.3; 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 6.0.2; version 0.1 only; version 0.2 only; version 0.3 only; version 0.4 only; version 0.5 only; …

Published 2011-09-29. Last modified 2026-06-16.