core/html/parser/XSSAuditor.cpp in the XSS auditor in Blink, as used in Google Chrome before 33.0.1750.117, inserts the about:blank URL during certain blocking of FORM elements within HTTP requests, which allows remote attackers to bypass the Same Origin Policy and obtain sensitive information via unspecified vectors.
https://src.chromium.org/viewvc/blink?revision=164538&view=revision
https://code.google.com/p/chromium/issues/detail?id=331060
http://www.debian.org/security/2014/dsa-2883
http://lists.opensuse.org/opensuse-updates/2014-03/msg00006.html
http://googlechromereleases.blogspot.com/2014/02/stable-channel-update_20.html