Integer overflow in the strxfrm function in the GNU C Library (aka glibc or libc6) before 2.21 allows context-dependent attackers to cause a denial of service (crash) or possibly execute arbitrary code via a long string, which triggers a stack-based buffer overflow.
https://sourceware.org/git/gitweb.cgi?p=glibc.git%3Bh=0f9e585480ed
https://sourceware.org/bugzilla/show_bug.cgi?id=16009
http://www.securityfocus.com/bid/72602