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 b2b12c8f138bfeace215e47cc36cc2f3a5b33df6..da5283735c97e890e57b705b3c87a2723823873d 100644
--- a/src/crypto/elliptic/p256.go
+++ b/src/crypto/elliptic/p256.go
@@ -52,7 +52,7 @@ 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 1435f5e1a58a8f9a7f1a9cffe7d5ca03f08f79c7..694186df8137232499fb853562b75d827914f014 100644
--- a/src/crypto/elliptic/p256_test.go
+++ b/src/crypto/elliptic/p256_test.go
@@ -153,3 +153,17 @@ 	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)
+	}
+}