Description:

Mozilla has published security advisories to address multiple vulnerabilities found in Firefox. These vulnerabilities are caused by memory safety bugs in the browser engine, use-after-free error, integer overflows when handling MPEG4 video and buffer overflows in the Libvpx library used for WebM video. A remote attacker could entice a user to open a web page with specially crafted content to exploit the vulnerabilities.

Affected Systems:

• Firefox prior to version 40
• Firefox ESR 38.x prior to version 38.2
  (Firefox ESR 31.x could also be affected but it has reached end-of-support)

Impact:

Depending on the vulnerability exploited, a successful attack could lead to application crash, bypass of security restrictions, elevation of privilege and arbitrary code execution.

Recommendation:

Mozilla has released new versions of the products to address the issues and they can be downloaded at the following URLs:

• Firefox 40 for Windows, Macintosh and Linux
  http://www.mozilla.org/en-US/firefox/all.html
  
  
• Firefox ESR 38.2 for Windows, Macintosh and Linux
  http://www.mozilla.org/en-US/firefox/organizations/all/
  
  

Users of affected systems should follow the recommendations provided by the product vendor and take immediate actions to mitigate the risk.

More Information:

https://www.mozilla.org/en-US/security/advisories/
https://www.mozilla.org/en-US/security/advisories/mfsa2015-79/
https://www.mozilla.org/en-US/security/advisories/mfsa2015-80/
https://www.mozilla.org/en-US/security/advisories/mfsa2015-81/
https://www.mozilla.org/en-US/security/advisories/mfsa2015-82/
https://www.mozilla.org/en-US/security/advisories/mfsa2015-83/
https://www.mozilla.org/en-US/security/advisories/mfsa2015-84/
https://www.mozilla.org/en-US/security/advisories/mfsa2015-85/
https://www.mozilla.org/en-US/security/advisories/mfsa2015-86/
https://www.mozilla.org/en-US/security/advisories/mfsa2015-87/
https://www.mozilla.org/en-US/security/advisories/mfsa2015-88/
https://www.mozilla.org/en-US/security/advisories/mfsa2015-89/
https://www.mozilla.org/en-US/security/advisories/mfsa2015-90/
https://www.mozilla.org/en-US/security/advisories/mfsa2015-91/
https://www.mozilla.org/en-US/security/advisories/mfsa2015-92/
https://wiki.mozilla.org/Enterprise/Firefox/ExtendedSupport:Proposal
https://www.hkcert.org/my_url/en/alert/15081216
https://www.us-cert.gov/ncas/current-activity/2015/08/11/Mozilla-Releases-Security-Updates-Firefox-Firefox-ESR-and-Firefox
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4473 (to CVE-2015-4475)
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4477 (to CVE-2015-4493)