| Description: | USN-853-1 fixed vulnerabilities in Firefox and Xulrunner. The upstream changes introduced regressions that could lead to crashes when processing certain malformed GIF images, fonts and web pages. This update fixes the problem. We apologize for the inconvenience. Original advisory details: Alin Rad Pop discovered a heap-based buffer overflow in Firefox when it converted strings to floating point numbers. If a user were tricked into viewing a malicious website, a remote attacker could cause a denial of service or possibly execute arbitrary code with the privileges of the user invoking the program. Jeremy Brown discovered that the Firefox Download Manager was vulnerable to symlink attacks. A local attacker could exploit this to create or overwrite files with the privileges of the user invoking the program. Paul Stone discovered a flaw in the Firefox form history. If a user were tricked into viewing a malicious website, a remote attacker could access this data to steal confidential information. Orlando Berrera discovered that Firefox did not properly free memory when using web-workers. If a user were tricked into viewing a malicious website, a remote attacker could cause a denial of service or possibly execute arbitrary code with the privileges of the user invoking the program. This issue only affected Ubuntu 9.10. A flaw was discovered in the way Firefox processed Proxy Auto-configuration files. If a user configured the browser to use PAC files with certain regular expressions, an attacker could cause a denial of service or possibly execute arbitrary code with the privileges of the user invoking the program. A heap-based buffer overflow was discovered in Mozilla�s GIF image parser. If a user were tricked into viewing a malicious website, a remote attacker could cause a denial of service or possibly execute arbitrary code with the privileges of the user invoking the program. A flaw was discovered in the JavaScript engine of Firefox. An attacker could exploit this to execute scripts from page content with chrome privileges. Gregory Fleischer discovered that the same-origin check in Firefox could be bypassed by utilizing the document.getSelection function. An attacker could exploit this to read data from other domains. Jesse Ruderman and Sid Stamm discovered that Firefox did not properly display filenames containing right-to-left override characters. If a user were tricked into downloading a malicious file with a crafted filename, an attacker could exploit this to trick the user into opening a different file than the user expected. Several flaws were discovered in third party media libraries. If a user were tricked into opening a crafted media file, a remote attacker could cause a denial of service or possibly execute arbitrary code with the privileges of the user invoking the program. This issue only affected Ubuntu 9.10. Vladimir Vukicevic, Jesse Ruderman, Martijn Wargers, Daniel Banchero, David Keeler, Boris Zbarsky, Thomas Frederiksen, Marcia Knous, Carsten Book, Kevin Brosnan, David Anderson and Jeff Walden discovered various flaws in the browser and JavaScript engines of Firefox. If a user were tricked into viewing a malicious website, a remote attacker could cause a denial of service or possibly execute arbitrary code with the privileges of the user invoking the program |