diff --git a/src/script/sign.h b/src/script/sign.h
--- a/src/script/sign.h
+++ b/src/script/sign.h
@@ -202,6 +202,9 @@
                          const std::map<CPubKey, KeyOriginInfo> &hd_keypaths,
                          uint8_t type) {
     for (auto keypath_pair : hd_keypaths) {
+        if (!keypath_pair.first.IsValid()) {
+            throw std::ios_base::failure("Invalid CPubKey being serialized");
+        }
         SerializeToVector(s, type, MakeSpan(keypath_pair.first));
         WriteCompactSize(s, (keypath_pair.second.path.size() + 1) *
                                 sizeof(uint32_t));