From 9d892099378b2ad5f52220403bdeae43c61d6955 Mon Sep 17 00:00:00 2001
From: Greg Sanders <gsanders87@gmail.com>
Date: Fri, 3 Nov 2023 09:21:48 -0400
Subject: [PATCH] policy: stop 3rd party wtxid malleability of anchor spend

---
 src/policy/policy.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/policy/policy.cpp b/src/policy/policy.cpp
index e84a8428bf2..68d879b5b81 100644
--- a/src/policy/policy.cpp
+++ b/src/policy/policy.cpp
@@ -225,6 +225,11 @@ bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs)
         // get the scriptPubKey corresponding to this input:
         CScript prevScript = prev.scriptPubKey;
 
+        // witness stuffing detected
+        if (prevScript.IsPayToAnchor()) {
+            return false;
+        }
+
         bool p2sh = false;
         if (prevScript.IsPayToScriptHash()) {
             std::vector <std::vector<unsigned char> > stack;