The MediaElementAudioSourceNode::process function in modules/webaudio/MediaElementAudioSourceNode.cpp in the Web Audio API implementation in Blink, as used in Google Chrome before 42.0.2311.90, allows remote attackers to bypass the Same Origin Policy and obtain sensitive audio sample values via a crafted web site containing a media element.
https://src.chromium.org/viewvc/blink?revision=189527&view=revision
https://security.gentoo.org/glsa/201506-04
https://code.google.com/p/chromium/issues/detail?id=313939
http://www.securitytracker.com/id/1032209
http://www.debian.org/security/2015/dsa-3238
http://ubuntu.com/usn/usn-2570-1
http://rhn.redhat.com/errata/RHSA-2015-0816.html
http://lists.opensuse.org/opensuse-updates/2015-11/msg00024.html
http://lists.opensuse.org/opensuse-updates/2015-04/msg00040.html
http://googlechromereleases.blogspot.com/2015/04/stable-channel-update_14.html