diff --git a/src/node_crypto.cc b/src/node_crypto.cc
index fa85f7855371b5..38ee6af5dac7ec 100644
--- a/src/node_crypto.cc
+++ b/src/node_crypto.cc
@@ -5513,8 +5513,9 @@ bool PublicKeyCipher::Cipher(Environment* env,
     // OpenSSL takes ownership of the label, so we need to create a copy.
     void* label = OPENSSL_memdup(oaep_label, oaep_label_len);
     CHECK_NOT_NULL(label);
-    if (0 >= EVP_PKEY_CTX_set0_rsa_oaep_label(ctx.get(), label,
-                                              oaep_label_len)) {
+    if (0 >= EVP_PKEY_CTX_set0_rsa_oaep_label(ctx.get(),
+                reinterpret_cast<unsigned char*>(label),
+                                      oaep_label_len)) {
       OPENSSL_free(label);
       return false;
     }