Launchpad.net

CVE 2015-2733

Use-after-free vulnerability in the CanonicalizeXPCOMParticipant function in Mozilla Firefox before 39.0 and Firefox ESR 31.x before 31.8 and 38.x before 38.1 allows remote attackers to execute arbitrary code via vectors involving attachment of an XMLHttpRequest object to a dedicated worker.

See the CVE page on Mitre.org for more details.