In the GNU C Library through 2.29, proceed_next_node in posix/regexec.c has a heap-based buffer over-read via an attempted case-insensitive regular-expression match. A flaw was found in glibc. If an attacker provides the iconv function with invalid multi-byte input sequences in IBM1364, IBM1371, IBM1388, IBM1390, IBM1399 encodings, it fails to advance the input state, which could lead to an infinite loop in applications, resulting in a denial of service