diff --git a/hw/virtio/virtio-crypto.c b/hw/virtio/virtio-crypto.c
index 517f2089c5..b20f299937 100644
--- a/hw/virtio/virtio-crypto.c
+++ b/hw/virtio/virtio-crypto.c
@@ -767,11 +767,18 @@ virtio_crypto_handle_asym_req(VirtIOCrypto *vcrypto,
     uint32_t len;
     uint8_t *src = NULL;
     uint8_t *dst = NULL;
+    uint64_t max_len;
 
     asym_op_info = g_new0(CryptoDevBackendAsymOpInfo, 1);
     src_len = ldl_le_p(&req->para.src_data_len);
     dst_len = ldl_le_p(&req->para.dst_data_len);
 
+    max_len = (uint64_t)src_len + dst_len;
+    if (unlikely(max_len > vcrypto->conf.max_size)) {
+        virtio_error(vdev, "virtio-crypto asym request is too large");
+        goto err;
+    }
+
     if (src_len > 0) {
         src = g_malloc0(src_len);
         len = iov_to_buf(iov, out_num, 0, src, src_len);