net/PacProxySelector.java in the Proxy Auto-Config (PAC) feature in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before 2016-07-01 does not ensure that URL information is restricted to a scheme, host, and port, which allows remote attackers to discover credentials by operating a server with a PAC script, aka internal bug 27593919.
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.