diff --git a/contract/contract/src/crowdfunding.rs b/contract/contract/src/crowdfunding.rs
index 4a78136..31d3ade 100644
--- a/contract/contract/src/crowdfunding.rs
+++ b/contract/contract/src/crowdfunding.rs
@@ -323,6 +323,9 @@ impl CrowdfundingTrait for CrowdfundingContract {
 
         buyer.require_auth();
 
+        // ── reentrancy lock ──────────────────────────────────────────────────
+        reentrancy_lock_logic(&env, pool_id)?;
+
         // ── fee split ────────────────────────────────────────────────────────
         let fee_bps: u32 = env
             .storage()
diff --git a/contract/contract/test/buy_ticket_reentrancy_test.rs b/contract/contract/test/buy_ticket_reentrancy_test.rs
new file mode 100644
index 0000000..d5f09b0
--- /dev/null
+++ b/contract/contract/test/buy_ticket_reentrancy_test.rs
@@ -0,0 +1,108 @@
+#![cfg(test)]
+
+use soroban_sdk::{testutils::Address as _, token, Address, Env};
+
+use crate::{
+    base::{errors::CrowdfundingError, types::PoolConfig, types::StorageKey},
+    crowdfunding::{CrowdfundingContract, CrowdfundingContractClient},
+};
+
+fn setup(env: &Env) -> (CrowdfundingContractClient<'_>, Address, Address) {
+    env.mock_all_auths();
+    let contract_id = env.register(CrowdfundingContract, ());
+    let client = CrowdfundingContractClient::new(env, &contract_id);
+
+    let admin = Address::generate(env);
+    let token_admin = Address::generate(env);
+    let token = env
+        .register_stellar_asset_contract_v2(token_admin)
+        .address();
+
+    client.initialize(&admin, &token, &0);
+    (client, admin, token)
+}
+
+fn create_pool(client: &CrowdfundingContractClient<'_>, env: &Env, token: &Address) -> u64 {
+    let creator = Address::generate(env);
+    let config = PoolConfig {
+        name: soroban_sdk::String::from_str(env, "Ticket Pool"),
+        description: soroban_sdk::String::from_str(env, "reentrancy test"),
+        target_amount: 1_000_000,
+        min_contribution: 0,
+        is_private: false,
+        duration: 86_400,
+        created_at: env.ledger().timestamp(),
+        token_address: token.clone(),
+    };
+    client.create_pool(&creator, &config)
+}
+
+/// Verify that the reentrancy lock is set during buy_ticket by checking that
+/// a concurrent call on the same pool is rejected with Unauthorized while the
+/// lock is held, and that the lock is released cleanly after the call so a
+/// subsequent call succeeds.
+#[test]
+fn test_buy_ticket_reentrancy_lock_engaged_and_released() {
+    let env = Env::default();
+    let (client, _, token) = setup(&env);
+    let pool_id = create_pool(&client, &env, &token);
+
+    // Manually set the reentrancy lock to simulate a concurrent in-flight call
+    env.as_contract(&client.address, || {
+        env.storage()
+            .instance()
+            .set(&StorageKey::ReentrancyLock(pool_id), &true);
+    });
+
+    // buy_ticket must be rejected while the lock is held
+    let buyer = Address::generate(&env);
+    let token_client = token::StellarAssetClient::new(&env, &token);
+    token_client.mint(&buyer, &1_000);
+
+    let result = client.try_buy_ticket(&pool_id, &buyer, &token, &1_000);
+    assert_eq!(
+        result,
+        Err(Ok(CrowdfundingError::Unauthorized)),
+        "buy_ticket must be blocked while the reentrancy lock is held"
+    );
+
+    // Release the lock (simulates the original call completing)
+    env.as_contract(&client.address, || {
+        env.storage()
+            .instance()
+            .remove(&StorageKey::ReentrancyLock(pool_id));
+    });
+
+    // After the lock is released, buy_ticket must succeed
+    let result = client.try_buy_ticket(&pool_id, &buyer, &token, &1_000);
+    assert_eq!(
+        result,
+        Ok(Ok((1_000, 0))),
+        "buy_ticket must succeed once the reentrancy lock is released"
+    );
+}
+
+/// Verify that the lock is released after a successful buy_ticket call so
+/// subsequent calls on the same pool are not permanently blocked.
+#[test]
+fn test_buy_ticket_lock_released_after_success() {
+    let env = Env::default();
+    let (client, _, token) = setup(&env);
+    let pool_id = create_pool(&client, &env, &token);
+
+    let buyer = Address::generate(&env);
+    let token_client = token::StellarAssetClient::new(&env, &token);
+    token_client.mint(&buyer, &2_000);
+
+    // First call succeeds
+    assert_eq!(
+        client.try_buy_ticket(&pool_id, &buyer, &token, &1_000),
+        Ok(Ok((1_000, 0)))
+    );
+
+    // Second call also succeeds — lock was released after the first
+    assert_eq!(
+        client.try_buy_ticket(&pool_id, &buyer, &token, &1_000),
+        Ok(Ok((1_000, 0)))
+    );
+}
diff --git a/contract/contract/test/mod.rs b/contract/contract/test/mod.rs
index 112a510..c7739e2 100644
--- a/contract/contract/test/mod.rs
+++ b/contract/contract/test/mod.rs
@@ -2,6 +2,7 @@ mod all_events_test;
 // mod blacklist_test; // Features not yet implemented
 mod batch_claim_test;
 mod buy_ticket_test;
+mod buy_ticket_reentrancy_test;
 mod close_pool_test;
 mod close_private_pool_test;
 mod create_event_test;