Late last month news hit the web about a remote code execution exploit that affected as many as 950 million phones running Google's Android operating system. The attack was called Stagefright, it enabled an attacker to infect a phone via a single MMS message but was supposedly patches by Google and Samsung in early August.
Unfortunately, The Tech Report writes Android devices are still at risk because the patch for the Stagefright security bugs did not fully protect devices. It appears it's still possible to create a buffer overflow and execute code via a malformed MP4 file:
The Exodus blog post walks through the vulnerability. A function in libStagefright reads two values from an MP4 file's header, chunk_size and chunk_type, as 32-bit integers. If the header returns a value of 0x01 for chunk_size, then a 64-bit value is read from the MP4 instead. According to the researchers, if an MP4 is crafted with a chunk size of 0x1fffffff (or any other value outside the bounds of a 32-bit integer), a flaw in the Stagefright patch's boundary-checking code means it's still possible to cause a buffer overflow.