Use size of entries, not size of the pointer.
GH:
@@ -720,7 +720,7 @@ SSL *SSL_new(SSL_CTX *ctx)
s->ext.supportedgroups =
OPENSSL_memdup(ctx->ext.supportedgroups,
ctx->ext.supportedgroups_len
- * sizeof(ctx->ext.supportedgroups));
+ * sizeof(*ctx->ext.supportedgroups));
if (!s->ext.supportedgroups)
goto err;
s->ext.supportedgroups_len = ctx->ext.supportedgroups_len;
