--- a/zlib_interface.c
+++ b/zlib_interface.c
@@ -93,7 +93,7 @@ int jg_zlib_uncompress(void const *in_buf, int in_size,
				free(out_buf);
				if (JG_ZLIB_DEBUG) {
					snprintf (tmpstring, sizeof(tmpstring), "ERROR: zlib_uncompress: %d %s\n", result, stream.msg);
-					fprintf(stderr, tmpstring);
+					fprintf(stderr, "%s", tmpstring);
				}
				return JG_ZLIB_ERROR_UNCOMPRESS;
		}
