diff --git a/colortest.cpp b/colortest.cpp
index 09ca9dba3a690e1eaeb5b3e77f5c2d5ec3594dc5..4616be12399a5be8f360535978779c28af943ae6 100644
--- a/colortest.cpp
+++ b/colortest.cpp
@@ -53,7 +53,7 @@ int main(int argc, char **argv)
 	WriteImageVerb(out, outname, verbose);
     }
     catch (CError &err) {
-	fprintf(stderr, err.message);
+	fprintf(stderr, "%s", err.message);
 	fprintf(stderr, "\n");
 	exit(1);
     }