diff --git a/common/env_attr.c b/common/env_attr.c
index 3862190..f965b4b 100644
--- a/common/env_attr.c
+++ b/common/env_attr.c
@@ -132,6 +132,10 @@ static int regex_callback(const char *name, const char *attributes, void *priv)
 		if (slre_match(&slre, cbp->searched_for,
 			       strlen(cbp->searched_for), caps)) {
 			free(cbp->regex);
+			if (!attributes) {
+				retval = -EINVAL;
+				goto done;
+			}
 			cbp->regex = malloc(strlen(regex) + 1);
 			if (cbp->regex) {
 				strcpy(cbp->regex, regex);