Firefox 3.5.3 fixes critical security vulnerabilities

Mozilla released Firefox 3.5.3 that fixes several security issues.

Crashes with evidence of memory corruption
Mozilla developers and community members identified and fixed several stability bugs in the browser engine used in Firefox and other Mozilla-based products. Some of these crashes showed evidence of memory corruption under certain circumstances and we presume that with enough effort at least some of these could be exploited to run arbitrary code.

TreeColumns dangling pointer vulnerability
The columns of a XUL tree element could be manipulated in a particular way which would leave a pointer owned by the column pointing to freed memory. An attacker could potentially use this vulnerability to crash a victim’s browser and run arbitrary code on the victim’s computer.

Location bar spoofing via tall line-height Unicode characters
The default Windows font used to render the locationbar and other text fields was improperly displaying certain Unicode characters with tall line-height. In such cases the tall line-height would cause the rest of the text in the input field to be scrolled vertically out of view. An attacker could use this vulnerability to prevent a user from seeing the URL of a malicious site.

Chrome privilege escalation with FeedWriter
The BrowserFeedWriter could be leveraged to run JavaScript code from web content with elevated privileges. Using this vulnerability, an attacker could construct an object containing malicious JavaScript and cause the FeedWriter to process the object, running the malicious code with chrome privileges.