diff --git a/src/addrman.h b/src/addrman.h
--- a/src/addrman.h
+++ b/src/addrman.h
@@ -499,6 +499,7 @@
     }
 
     void Clear() {
+        LOCK(cs);
         std::vector<int>().swap(vRandom);
         nKey = GetRandHash();
         for (size_t bucket = 0; bucket < ADDRMAN_NEW_BUCKET_COUNT; bucket++) {