Multiple integer overflows in the (1) chk_malloc, (2) leak_malloc, and (3) leak_memalign functions in libc/bionic/malloc_debug_leak.c in Bionic (libc) for Android, when libc.debug.malloc is set, make it easier for context-dependent attackers to perform memory-related attacks such as buffer overflows via a large size value, which causes less memory to be allocated than expected.
http://www.openwall.com/lists/oss-security/2012/06/07/13
http://www.openwall.com/lists/oss-security/2012/06/05/1
http://kqueue.org/blog/2012/03/05/memory-allocator-security-revisited/