diff --git a/funcs/func_strings.c b/funcs/func_strings.c
index a389eaf4156a993c3ac564024ff4b02b798321da..fa0174c60d1a3fa5b6669e72f81e243cd150436a 100644
--- a/funcs/func_strings.c
+++ b/funcs/func_strings.c
@@ -552,7 +552,7 @@ static int listfilter(struct ast_channel *chan, const char *cmd, char *parse, ch
 				ast_str_append(result_ptr, len, "%s", delim);
 			}
 
-			ast_str_append_substr(result_ptr, len, begin, cur - begin + 1);
+			ast_str_append_substr(result_ptr, len, begin, cur - begin);
 			first = 0;
 			begin = cur + dlen;
 		}