diff -ur libsodium-1.0.18-orig/src/libsodium/crypto_sign/ed25519/ref10/open.c libsodium-1.0.18/src/libsodium/crypto_sign/ed25519/ref10/open.c
--- libsodium-1.0.18-orig/src/libsodium/crypto_sign/ed25519/ref10/open.c	2019-05-18 16:32:11.000000000 -0400
+++ libsodium-1.0.18/src/libsodium/crypto_sign/ed25519/ref10/open.c	2020-01-21 18:55:22.474233831 -0500
@@ -32,8 +32,11 @@
         ge25519_has_small_order(sig) != 0) {
         return -1;
     }
-    if (ge25519_is_canonical(pk) == 0 ||
-        ge25519_has_small_order(pk) != 0) {
+    unsigned char d = 0;
+    for (int i = 0; i < 32; ++i) {
+        d |= pk[i];
+    }
+    if (d == 0) {
         return -1;
     }
 #endif