Ubuntu Security Notice 5709-1 - Multiple security issues were discovered in Firefox. If a user were tricked into opening a specially crafted website, an attacker could potentially exploit these to cause a denial of service, obtain sensitive information across domains, or execute arbitrary code. It was discovered that Firefox saved usernames to a plaintext file. A local user could potentially exploit this to obtain sensitive information.
22fb1de6370e876fd1532ba4ae21c288f4fca5714d04f96592e871e0107d0ec9