Integer underflow in the MPEG4Extractor::parseChunk function in MPEG4Extractor.cpp in libstagefright in mediaserver in Android before 5.1.1 LMY48M allows remote attackers to execute arbitrary code via crafted MPEG-4 data, aka internal bug 23034759. NOTE: this vulnerability exists because of an incomplete fix for CVE-2015-3824.
https://www.exploit-db.com/exploits/40436/
https://www.exploit-db.com/exploits/39640/
https://www.exploit-db.com/exploits/38226/
https://groups.google.com/forum/message/raw?msg=android-security-updates/1M7qbSvACjo/Y7jewiW1AwAJ
https://blog.zimperium.com/reflecting-on-stagefright-patches/
https://blog.zimperium.com/cve-2015-3864-metasploit-module-now-available-for-testing/
https://android.googlesource.com/platform/frameworks/av/+/6fe85f7e15203e48df2cc3e8e1c4bc6ad49dc968