diff --git a/contracts/escrow-vault/src/lib.rs b/contracts/escrow-vault/src/lib.rs
index 8287092..409cb8e 100644
--- a/contracts/escrow-vault/src/lib.rs
+++ b/contracts/escrow-vault/src/lib.rs
@@ -503,7 +503,7 @@ impl EscrowVaultContract {
         let refund = escrow.locked_amount;
 
         escrow.locked_amount = 0;
-        escrow.refunded_amount = refund;
+        escrow.refunded_amount += refund;
         escrow.state = EscrowState::Refunded;
 
         let _ttl_key = DataKey::Escrow(escrow_id);
diff --git a/contracts/liquidity-pool/src/lib.rs b/contracts/liquidity-pool/src/lib.rs
index fb9354b..94906f7 100644
--- a/contracts/liquidity-pool/src/lib.rs
+++ b/contracts/liquidity-pool/src/lib.rs
@@ -189,7 +189,10 @@ impl LiquidityPoolContract {
         if total_shares == 0 {
             panic!("no shares in pool");
         }
-        let amount = (shares * pool.total_liquidity) / total_shares;
+        let amount = shares
+            .checked_mul(pool.total_liquidity)
+            .expect("share redemption calculation overflows i128")
+            / total_shares;
         let available = pool.total_liquidity - pool.total_borrowed;
 
         if amount > available {
diff --git a/contracts/milestone-tracker/src/lib.rs b/contracts/milestone-tracker/src/lib.rs
index e18bf87..38fcf85 100644
--- a/contracts/milestone-tracker/src/lib.rs
+++ b/contracts/milestone-tracker/src/lib.rs
@@ -98,7 +98,8 @@ impl MilestoneTrackerContract {
         }
 
         let now = env.ledger().timestamp();
-        let deadline = now + duration_secs;
+        let deadline = now.checked_add(duration_secs)
+            .expect("milestone deadline timestamp overflows u64");
 
         let counter: u64 = env
             .storage()