The stringprep_utf8_to_ucs4 function in libin before 1.31, as used in jabberd2, allows context-dependent attackers to read system memory and possibly have other unspecified impact via invalid UTF-8 characters in a string, which triggers an out-of-bounds read. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-2059