The Android WebView in Android before 4.4 allows remote attackers to bypass the Same Origin Policy via a crafted attribute containing a \u0000 character, as demonstrated by an onclick="window.open('\u0000javascript: sequence to the Android Browser application 4.2.1 or a third-party web browser.

The Android browser in Android cannot properly restrict modifications to cookies established in HTTPS sessions, which allows man-in-the-middle attackers to overwrite or delete arbitrary cookies via a Set-Cookie header in an HTTP response, related to lack of the HTTP Strict Transport Security (HSTS) includeSubDomains feature, aka a "cookie forcing" issue.