diff --git a/contracts/BatchExecutor.sol b/contracts/BatchExecutor.sol
index ccba38c..f85d056 100644
--- a/contracts/BatchExecutor.sol
+++ b/contracts/BatchExecutor.sol
@@ -7,14 +7,19 @@ pragma solidity ^0.8.20;
 ///
 /// receive/fallback are required so other delegated EOAs can still accept
 /// plain ETH value transfers from multiSend (empty calldata must not revert).
+///
+/// multiSend is onlySelf: without `msg.sender == address(this)`, any third
+/// party could call a delegated EOA and drain its ETH.
 contract BatchExecutor {
     receive() external payable {}
 
     fallback() external payable {}
 
     /// @notice Transfer ETH to multiple recipients.
-    /// @dev Must be called as the delegated EOA (to == EOA after set-code).
+    /// @dev Must be called as the delegated EOA (to == EOA after set-code),
+    ///      and only by the EOA itself (msg.sender == address(this)).
     function multiSend(address[] calldata recipients, uint256[] calldata amounts) external payable {
+        require(msg.sender == address(this), "only self");
         uint256 n = recipients.length;
         require(n == amounts.length, "len");
         for (uint256 i = 0; i < n; ) {
diff --git a/src/txn_plan/constructor/eip7702.rs b/src/txn_plan/constructor/eip7702.rs
index 3b73fd9..07ceff7 100644
--- a/src/txn_plan/constructor/eip7702.rs
+++ b/src/txn_plan/constructor/eip7702.rs
@@ -146,31 +146,35 @@ pub const EIP7702_DELEGATE_DEPLOY_GAS_LIMIT: u64 = 500_000;
 /// Runtime exposes `multiSend(address[],uint256[])` (selector `0xbb4c9f0b`).
 /// Designed as an EIP-7702 delegation target: after set-code, call the EOA
 /// with multiSend so value transfers use the EOA balance.
+/// `multiSend` requires `msg.sender == address(this)` (onlySelf).
 pub fn delegate_contract_bytecode() -> Vec<u8> {
     // solc --bin --optimize --optimize-runs 200 contracts/BatchExecutor.sol
     // Includes receive/fallback so multiSend into already-delegated EOAs succeeds.
+    // Includes onlySelf guard so third parties cannot drain delegated EOAs.
     const HEX: &str = concat!(
-        "608060405234801561000f575f80fd5b506102778061001d5f395ff3fe608060",
+        "608060405234801561000f575f80fd5b506102b28061001d5f395ff3fe608060",
         "40526004361061001e575f3560e01c8063bb4c9f0b1461002757005b36610025",
-        "57005b005b610025610035366004610199565b82818114610070576040516246",
+        "57005b005b6100256100353660046101d4565b3330146100755760405162461b",
+        "cd60e51b815260206004820152600960248201526837b7363c9039b2b63360b9",
+        "1b60448201526064015b60405180910390fd5b828181146100ab576040516246",
         "1bcd60e51b81526020600482015260036024820152623632b760e91b60448201",
-        "526064015b60405180910390fd5b5f5b81811015610149575f86868381811061",
-        "008d5761008d610200565b90506020020160208101906100a29190610214565b",
-        "6001600160a01b03168585848181106100bd576100bd610200565b9050602002",
-        "01356040515f6040518083038185875af1925050503d805f8114610101576040",
-        "519150601f19603f3d011682016040523d82523d5f602084013e610106565b60",
-        "6091505b50509050806101405760405162461bcd60e51b815260040161006790",
-        "6020808252600490820152631cd95b9960e21b604082015260600190565b5060",
-        "0101610072565b505050505050565b5f8083601f840112610161575f80fd5b50",
-        "813567ffffffffffffffff811115610178575f80fd5b60208301915083602082",
-        "60051b8501011115610192575f80fd5b9250929050565b5f805f806040858703",
-        "12156101ac575f80fd5b843567ffffffffffffffff808211156101c3575f80fd",
-        "5b6101cf88838901610151565b909650945060208701359150808211156101e7",
-        "575f80fd5b506101f487828801610151565b95989497509550505050565b634e",
-        "487b7160e01b5f52603260045260245ffd5b5f60208284031215610224575f80",
-        "fd5b81356001600160a01b038116811461023a575f80fd5b939250505056fea2",
-        "646970667358221220a2fc7415ad69a852d05958c007f06988587d8766968d3b",
-        "7a734a15534d07c51064736f6c63430008150033",
+        "5260640161006c565b5f5b81811015610184575f8686838181106100c8576100",
+        "c861023b565b90506020020160208101906100dd919061024f565b6001600160",
+        "a01b03168585848181106100f8576100f861023b565b90506020020135604051",
+        "5f6040518083038185875af1925050503d805f811461013c576040519150601f",
+        "19603f3d011682016040523d82523d5f602084013e610141565b606091505b50",
+        "5090508061017b5760405162461bcd60e51b815260040161006c906020808252",
+        "600490820152631cd95b9960e21b604082015260600190565b506001016100ad",
+        "565b505050505050565b5f8083601f84011261019c575f80fd5b50813567ffff",
+        "ffffffffffff8111156101b3575f80fd5b6020830191508360208260051b8501",
+        "0111156101cd575f80fd5b9250929050565b5f805f80604085870312156101e7",
+        "575f80fd5b843567ffffffffffffffff808211156101fe575f80fd5b61020a88",
+        "83890161018c565b90965094506020870135915080821115610222575f80fd5b",
+        "5061022f8782880161018c565b95989497509550505050565b634e487b7160e0",
+        "1b5f52603260045260245ffd5b5f6020828403121561025f575f80fd5b813560",
+        "01600160a01b0381168114610275575f80fd5b939250505056fea26469706673",
+        "58221220361e305cccaa6daee31e970d468e4f32aa66c7ac631d269ae432b086",
+        "4e4be77564736f6c63430008150033",
     );
     hex::decode(HEX).expect("invalid BatchExecutor creation bytecode hex")
 }