Index: main/rtp.c
===================================================================
--- main/rtp.c	(revision 209024)
+++ main/rtp.c	(working copy)
@@ -1834,6 +1834,9 @@
 
 		rtp->f.subclass = AST_FORMAT_T140;
 		header_end = memchr(data, ((*data) & 0x7f), rtp->f.datalen);
+		if (header_end == NULL) {
+			return &ast_null_frame;
+		}
 		header_end++;
 		
 		header_length = header_end - data;