By taking advantage of one or more vulnerabilities in Mozilla products, an attacker may be able to take control of your computer.

Systems Affected

• Mozilla Suite (Mozilla web browser, Mozilla Mail)
• Firefox web browser
• Thunderbird email client

Solution
Upgrade to the latest version
Mozilla has released updated versions of the affected products. You can download the latest versions:

• Mozilla
• Firefox
• Thunderbird

Description
There are vulnerabilities in various features of Mozilla's web browsers and email clients. Some of the vulnerabilities are connected to the way the application handles URLs or images. In one instance, an attacker could cause an application to crash or could take control of your computer by convincing you to view a malicious web site or email message.
For more technical information, see US-CERT Technical Alert TA04-261A.

From US-CERT