From 2bc32656498517fe58bd41dcbd0afd306d51d4b0 Mon Sep 17 00:00:00 2001
From: stringintech <stringintech@gmail.com>
Date: Wed, 17 Dec 2025 18:32:16 +0330
Subject: [PATCH] Fix `ChainstateManager::AddChainstate()` assertion crash

Check mempool exists before accessing size when prev_chainstate doesn't have initialized mempool.
---
 src/validation.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/validation.cpp b/src/validation.cpp
index 04f60e7bd56..277c4d3b72c 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -6248,7 +6248,7 @@ Chainstate& ChainstateManager::AddChainstate(std::unique_ptr<Chainstate> chainst
 
     // Transfer possession of the mempool to the chainstate.
     // Mempool is empty at this point because we're still in IBD.
-    assert(prev_chainstate.m_mempool->size() == 0);
+    assert(!prev_chainstate.m_mempool || prev_chainstate.m_mempool->size() == 0);
     assert(!curr_chainstate.m_mempool);
     std::swap(curr_chainstate.m_mempool, prev_chainstate.m_mempool);
     return curr_chainstate;