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.
https://news.ycombinator.com/item?id=8325807
https://news.ycombinator.com/item?id=8321185
https://exchange.xforce.ibmcloud.com/vulnerabilities/95693
https://android.googlesource.com/platform/external/webkit/+/7e4405a7a12750ee27325f065b9825c25b40598c
https://android.googlesource.com/platform/external/webkit/+/1368e05e8875f00e8d2529fe6050d08b55ea4d87