Google Chrome before 5.0.375.127 does not properly implement the notifications feature, which allows remote attackers to cause a denial of service (application crash) and possibly have unspecified other impact via unknown vectors.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12098
http://googlechromereleases.blogspot.com/2010/08/stable-channel-update_19.html