Index: pbx/pbx_config.c
===================================================================
--- pbx/pbx_config.c	(revision 171963)
+++ pbx/pbx_config.c	(working copy)
@@ -1403,6 +1403,39 @@
 	return 0;
 }
 
+static char *pbx_strsep(char **destructible, const char *delim)
+{
+	int paren = 0, square = 0, quote = 0;
+	char *res = *destructible;
+	for (; destructible && *destructible && **destructible; (*destructible)++) {
+		if (**destructible == '(' && !strchr(delim, '(')) {
+			paren++;
+		} else if (**destructible == ')' && !strchr(delim, ')')) {
+			if (paren) {
+				paren--;
+			}
+		} else if (**destructible == '[' && !strchr(delim, '[')) {
+			square++;
+		} else if (**destructible == ']' && !strchr(delim, ']')) {
+			if (square) {
+				square--;
+			}
+		} else if (**destructible == '"' && !strchr(delim, '"')) {
+			quote = quote ? 0 : 1;
+		} else if (**destructible == '\\' && !strchr(delim, '\\')) {
+			(*destructible)++;
+		} else if (strchr(delim, **destructible) && !paren && !quote && !square) {
+			**destructible = '\0';
+			(*destructible)++;
+			break;
+		}
+	}
+	if (destructible && *destructible && **destructible == '\0') {
+		*destructible = NULL;
+	}
+	return res;
+}
+
 static int pbx_load_config(const char *config_file)
 {
 	struct ast_config *cfg;
@@ -1488,7 +1521,7 @@
 					continue;
 				}
 
-				ext = S_OR(strsep(&stringp, ","), "");
+				ext = S_OR(pbx_strsep(&stringp, ","), "");
 				pbx_substitute_variables_helper(NULL, ext, realext, sizeof(realext) - 1);
 				ast_copy_string(lastextension, realext, sizeof(lastextension));
 process_extension:
@@ -1496,7 +1529,7 @@
 					*cidmatch++ = '\0';
 					ast_shrink_phone_number(cidmatch);
 				}
-				pri = S_OR(strsep(&stringp, ","), "");
+				pri = S_OR(pbx_strsep(&stringp, ","), "");
 				pri = ast_skip_blanks(pri);
 				pri = ast_trim_blanks(pri);
 				if ((label = strchr(pri, '('))) {
Index: main/pbx.c
===================================================================
--- main/pbx.c	(revision 171963)
+++ main/pbx.c	(working copy)
@@ -1900,6 +1900,9 @@
 						*s2++ = s3;
 					}
 					s1++; s1++;
+				} else if (*s1 == '\0') {
+					ast_log(LOG_WARNING, "A matching ']' was not found for '[' in pattern string '%s'\n", extenbuf);
+					break;
 				} else {
 					*s2++ = *s1++;
 				}