diff --git a/src/libsodium/crypto_scalarmult/ed25519/ref10/scalarmult_ed25519_ref10.c b/src/libsodium/crypto_scalarmult/ed25519/ref10/scalarmult_ed25519_ref10.c
index 57c06a58..0e317cf7 100644
--- a/src/libsodium/crypto_scalarmult/ed25519/ref10/scalarmult_ed25519_ref10.c
+++ b/src/libsodium/crypto_scalarmult/ed25519/ref10/scalarmult_ed25519_ref10.c
@@ -47,8 +47,8 @@ crypto_scalarmult_ed25519(unsigned char *q, const unsigned char *n,
     _crypto_scalarmult_ed25519_clamp(t);
     ge25519_scalarmult(&Q, t, &P);
     ge25519_p3_tobytes(q, &Q);
-    if (_crypto_scalarmult_ed25519_is_inf(q) != 0) {
-        return -1; /* LCOV_EXCL_LINE */
+    if (_crypto_scalarmult_ed25519_is_inf(q) != 0 || sodium_is_zero(n, 32)) {
+        return -1;
     }
     return 0;
 }
diff --git a/test/default/scalarmult_ed25519.c b/test/default/scalarmult_ed25519.c
index b1cf2ffd..3ad4bd09 100644
--- a/test/default/scalarmult_ed25519.c
+++ b/test/default/scalarmult_ed25519.c
@@ -43,10 +43,18 @@ main(void)
 
     memset(n, 0, crypto_scalarmult_ed25519_SCALARBYTES);
     if (crypto_scalarmult_ed25519_base(q, n) != -1) {
+        printf("crypto_scalarmult_ed25519_base(0) failed\n");
+    }
+    if (crypto_scalarmult_ed25519(q2, n, p) != -1) {
+        printf("crypto_scalarmult_ed25519(0) passed\n");
+    }
+
+    n[0] = 1;
+    if (crypto_scalarmult_ed25519_base(q, n) != 0) {
         printf("crypto_scalarmult_ed25519_base() failed\n");
     }
     if (crypto_scalarmult_ed25519(q2, n, p) != 0) {
-        printf("crypto_scalarmult_ed25519() failed\n");
+        printf("crypto_scalarmult_ed25519() passed\n");
     }
 
     if (crypto_scalarmult_ed25519(q, n, non_canonical_p) != -1) {