diff -up patchutils-0.3.4/src/filterdiff.c.format-str patchutils-0.3.4/src/filterdiff.c
--- patchutils-0.3.4/src/filterdiff.c.format-str	2017-05-15 11:54:20.203918650 +0100
+++ patchutils-0.3.4/src/filterdiff.c	2017-05-15 11:54:58.631833806 +0100
@@ -1355,7 +1355,7 @@ read_regex_file (const char *file)
 			char errstr[300];
 			regerror (err, &regex[num_regex - 1], errstr,
 				  sizeof (errstr));
-			error (EXIT_FAILURE, 0, errstr);
+			error (EXIT_FAILURE, 0, "%s", errstr);
 			exit (1);
 		}
 	}
@@ -1613,7 +1613,7 @@ int main (int argc, char *argv[])
 			char errstr[300];
 			regerror (err, &regex[num_regex - 1], errstr,
 				  sizeof (errstr));
-			error (EXIT_FAILURE, 0, errstr);
+			error (EXIT_FAILURE, 0, "%s", errstr);
 			exit (1);
 		}
 	}