What version of Go are you using (go version)?

Latest Go development branch

Does this issue reproduce with the latest release?

No. Tested latest using latest binary releases of Go 1.19 and 1.20; not affected, hence I'm creating a public bug report for this.

What operating system and processor architecture are you using (go env)?

Linux x64

What did you do?

package main

import (
	"crypto/elliptic"
	"fmt"
	"math/big"
)

func main() {
	curve := elliptic.P256()
	priv, _ := new(big.Int).SetString("115792089210356248762697446949407573529996955224135760342422259061068512044335", 10)
	x, y := curve.ScalarBaseMult(priv.Bytes())
	fmt.Println(x, ",", y)
}

https://go.dev/play/p/aTrVUdp0SkH?v=gotip

What did you expect to see?

21538630073048560509735576007149539115526969787353231629118474871518563178910 , 60188232952792585766986390787318113745120282298037326219660563054891997721808

What did you see instead?

0, 0