src/crypto/elliptic/p256.go      |  2 +-
 src/crypto/elliptic/p256_test.go | 14 ++++++++++++++

diff --git a/src/crypto/elliptic/p256.go b/src/crypto/elliptic/p256.go
index e1c6ff4f8791493a3a858e2c2edbb89a5f593f99..99c39ea9d544120febe86f53a0bdd64c89eee4db 100644
--- a/src/crypto/elliptic/p256.go
+++ b/src/crypto/elliptic/p256.go
@@ -51,7 +51,7 @@ func p256GetScalar(out *[32]byte, in []byte) {
 	n := new(big.Int).SetBytes(in)
 	var scalarBytes []byte
 
-	if n.Cmp(p256Params.N) >= 0 {
+	if n.Cmp(p256Params.N) >= 0 || len(in) > len(out) {
 		n.Mod(n, p256Params.N)
 		scalarBytes = n.Bytes()
 	} else {
diff --git a/src/crypto/elliptic/p256_test.go b/src/crypto/elliptic/p256_test.go
index c6862d95476c6fb8d40b247dfad1aa1fba531fac..a607766bc6cbf315ee2d1169665ec8cf57fcdae4 100644
--- a/src/crypto/elliptic/p256_test.go
+++ b/src/crypto/elliptic/p256_test.go
@@ -136,3 +136,17 @@ 	if x.Sign() != 0 || y.Sign() != 0 {
 		t.Errorf("1×G + (-1)×G = (%d, %d), should be ∞", x, y)
 	}
 }
+
+func TestIssue52075(t *testing.T) {
+	Gx, Gy := P256().Params().Gx, P256().Params().Gy
+	scalar := make([]byte, 33)
+	scalar[32] = 1
+	x, y := P256().ScalarBaseMult(scalar)
+	if x.Cmp(Gx) != 0 || y.Cmp(Gy) != 0 {
+		t.Errorf("unexpected output (%v,%v)", x, y)
+	}
+	x, y = P256().ScalarMult(Gx, Gy, scalar)
+	if x.Cmp(Gx) != 0 || y.Cmp(Gy) != 0 {
+		t.Errorf("unexpected output (%v,%v)", x, y)
+	}
+}