diff --git a/test/unittests/blockchaintest_runner_test.cpp b/test/unittests/blockchaintest_runner_test.cpp
index 6a28ea1870..f16abd5ca9 100644
--- a/test/unittests/blockchaintest_runner_test.cpp
+++ b/test/unittests/blockchaintest_runner_test.cpp
@@ -23,10 +23,9 @@ constexpr auto GENESIS_HASH = 0x9e11_bytes32;
 constexpr int64_t GAS_LIMIT = 0x100000;
 
 /// A fixture with one block that validate_block() accepts, for a test to then break in one way.
-/// BlockHeader has no default member initializers, hence the value-initialization.
 BlockchainTest one_block_fixture()
 {
-    BlockchainTest t{};
+    BlockchainTest t;
     t.name = "unit";
     t.network = "Prague";
 
@@ -37,7 +36,7 @@ BlockchainTest one_block_fixture()
     g.withdrawal_root = state::EMPTY_MPT_HASH;
     g.hash = GENESIS_HASH;
 
-    TestBlock b{};
+    TestBlock b;
     b.block_info.number = g.block_number + 1;
     b.block_info.parent_hash = g.hash;
     b.block_info.gas_limit = g.gas_limit;
diff --git a/test/utils/blockchaintest.hpp b/test/utils/blockchaintest.hpp
index 0fa18fc2a3..56ee86ec79 100644
--- a/test/utils/blockchaintest.hpp
+++ b/test/utils/blockchaintest.hpp
@@ -28,14 +28,14 @@ struct BlockHeader
     hash256 state_root;
     hash256 receipts_root;
     state::BloomFilter logs_bloom;
-    int64_t difficulty;
+    int64_t difficulty = 0;
     bytes32 prev_randao;
-    int64_t block_number;
-    int64_t gas_limit;
-    int64_t gas_used;
-    int64_t timestamp;
+    int64_t block_number = 0;
+    int64_t gas_limit = 0;
+    int64_t gas_used = 0;
+    int64_t timestamp = 0;
     bytes extra_data;
-    uint64_t base_fee_per_gas;
+    uint64_t base_fee_per_gas = 0;
     hash256 hash;
     hash256 transactions_root;
     hash256 withdrawal_root;