The ParamTraits<SkBitmap>::Read function in common/common_param_traits.cc in Google Chrome before 4.0.249.78 does not initialize the memory locations that will hold bitmap data, which might allow remote attackers to obtain potentially sensitive information from process memory by providing insufficient data, related to use of a (1) thumbnail database or (2) HTML canvas.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A14002
http://sites.google.com/a/chromium.org/dev/Home/chromium-security/chromium-security-bugs
http://securitytracker.com/id?1023506
http://googlechromereleases.blogspot.com/2010/01/stable-channel-update_25.html