diff --git a/lib/hx509/cert.c b/lib/hx509/cert.c
index 19136b345..3e6b31e3c 100644
--- a/lib/hx509/cert.c
+++ b/lib/hx509/cert.c
@@ -444,7 +444,7 @@ void
 hx509_verify_attach_anchors(hx509_verify_ctx ctx, hx509_certs set)
 {
     if (ctx->trust_anchors)
-	hx509_certs_free(ctx, ctx->trust_anchors);
+	hx509_certs_free(&ctx->trust_anchors);
     ctx->trust_anchors = _hx509_certs_ref(set);
 }