Ubuntu Security Notice USN-4649-2

Ubuntu Security Notice 4649-2 - USN-4649-1 fixed vulnerabilities in xdg-utils. That update caused a regression by removing the --attach functionality in thunderbird and others applications. This update fix the problem by reverting these changes. Jens Mueller discovered that xdg-utils incorrectly handled certain URI. An attacker could possibly use this issue to expose sensitive information. Various other issues were also addressed.
Ubuntu Security Notice USN-4649-2