diff --git a/lib/hx509/error.c b/lib/hx509/error.c
index 45813efb3..fc3cf90b3 100644
--- a/lib/hx509/error.c
+++ b/lib/hx509/error.c
@@ -67,8 +67,10 @@ free_error_string(hx509_error msg)
 void
 hx509_clear_error_string(hx509_context context)
 {
-    free_error_string(context->error);
-    context->error = NULL;
+    if (context) {
+	free_error_string(context->error);
+	context->error = NULL;
+    }
 }
 
 /**
@@ -91,6 +93,9 @@ hx509_set_error_stringv(hx509_context context, int flags, int code,
 {
     hx509_error msg;
 
+    if (context == NULL)
+	return;
+
     msg = calloc(1, sizeof(*msg));
     if (msg == NULL) {
 	hx509_clear_error_string(context);