Index: channels/misdn_config.c
===================================================================
--- channels/misdn_config.c	(revision 190576)
+++ channels/misdn_config.c	(working copy)
@@ -821,7 +821,9 @@
 				for (; iter; iter = iter->next) {
 					strncat(tempbuf, iter->msn, sizeof(tempbuf) - strlen(tempbuf) - 1);
 				}
-				tempbuf[strlen(tempbuf)-2] = 0;
+				if (strlen(tempbuf) > 1) {
+					tempbuf[strlen(tempbuf)-2] = 0;
+				}
 			}
 			snprintf(buf, bufsize, " -> msns: %s", *tempbuf ? tempbuf : "none");
 			break;