diff --git a/CHANGELOG.md b/CHANGELOG.md
index e28ea290..c19dcbaa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,6 +22,19 @@ change, not backfilled later.
   contract's `Unauthorized` variant remains (used in `extend_deadline`).
   Update client-side error decoders (`scripts/error-codes.mjs`) accordingly.
   (#319)
+- `compute_split` now rejects zero-bps recipients and duplicate addresses with
+  `InvalidSplit`, and it rejects self-payouts before any transfer executes
+  (#425).
+- Added explicit overflow error handling for arithmetic-boundary failures and
+  surfaced the dedicated `ArithmeticOverflow` family of variants instead of
+  relying on a host abort (#429).
+- Enforced the per-contract `MAX_DEPOSITS`/`TooManyDeposits` cap and added the
+  dedicated error code used by sponsor contribution flows (#427).
+- Typed contribution lookup failures (`ContributionNotFound` / related typed
+  errors) are now surfaced consistently instead of falling back to generic
+  logic (#421, #422).
+- Reclaim-window logic now aligns with the actual post-deadline grace-period
+  behavior used by the refund/recovery path (#423).
 
 ### Added
 - `CODEOWNERS`, pinning `contracts/`, `docs/` and `scripts/` review to the
@@ -39,7 +52,7 @@ change, not backfilled later.
 Escrows gained multi-sponsor crowdfunding: several sponsors can contribute
 toward one escrow's funding target instead of a single sponsor funding it
 outright, with a permissionless refund path once the deadline plus
-`GRACE_PERIOD` has passed and the target wasn't met.
+`GRACE_PERIOD` has passed, regardless of whether the target was met.
 
 ### Pause / circuit-breaker mechanism (#14)
 `escrow`, `maintenance-pool`, and `milestones` each gained `pause`/`unpause`
diff --git a/SECURITY.md b/SECURITY.md
index dd011247..082a2810 100644
--- a/SECURITY.md
+++ b/SECURITY.md
@@ -12,7 +12,7 @@ Older tagged releases are not actively patched. Please upgrade to the latest com
 
 **Do not open a public GitHub issue for security vulnerabilities.**
 
-Send a report by email to the maintainers listed in [CODEOWNERS](.github/CODEOWNERS) or use GitHub's private [Security Advisory](../../security/advisories/new) feature.
+Use GitHub's private [Security Advisory](../../security/advisories/new) feature for private disclosure. The repository does not publish an email address for security reports, and public issues or pull requests are not an acceptable disclosure channel.
 
 Include:
 
@@ -27,4 +27,4 @@ We will acknowledge receipt within **48 hours** and aim to provide a resolution
 
 This policy covers all Soroban smart contracts under the `contracts/` directory of this repository.
 
-Off-chain tooling (`scripts/`, `bindings/`) is in scope for disclosure but carries lower severity by default.
+Off-chain tooling under `scripts/` is in scope for disclosure but carries lower severity by default. The repository does not maintain a `bindings/` directory, so it is intentionally out of scope until a concrete implementation exists.
diff --git a/contracts/common/src/split.rs b/contracts/common/src/split.rs
index 9220f728..35e7154e 100644
--- a/contracts/common/src/split.rs
+++ b/contracts/common/src/split.rs
@@ -32,8 +32,9 @@ pub struct Payouts {
 /// already has, e.g. `compute_split(..).map_err(|_| Error::InvalidSplit)?`.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum SplitError {
-    /// `recipients` was empty, or its basis-point shares don't sum to
-    /// exactly `BPS_DENOMINATOR` (10000 = 100%).
+    /// `recipients` was empty; any share is zero; a recipient address appears
+    /// more than once; or the basis-point shares don't sum to exactly
+    /// `BPS_DENOMINATOR` (10000 = 100%).
     InvalidSplit,
     /// A recipient address equals the contract's own address — a self-payout
     /// that would strand funds in the contract with no recovery path.
@@ -56,6 +57,19 @@ pub fn compute_split(
         return Err(SplitError::InvalidSplit);
     }
 
+    for i in 0..recipients.len() {
+        let (recipient, bps) = recipients.get(i).unwrap();
+        if bps == 0 {
+            return Err(SplitError::InvalidSplit);
+        }
+        for j in 0..i {
+            let (other_recipient, _) = recipients.get(j).unwrap();
+            if recipient == other_recipient {
+                return Err(SplitError::InvalidSplit);
+            }
+        }
+    }
+
     let mut bps_sum: i128 = 0;
     for (_, bps) in recipients.iter() {
         bps_sum = bps_sum
diff --git a/contracts/common/src/test_fuzz.rs b/contracts/common/src/test_fuzz.rs
index 8e9a9aff..099f814b 100644
--- a/contracts/common/src/test_fuzz.rs
+++ b/contracts/common/src/test_fuzz.rs
@@ -278,6 +278,43 @@ mod tests {
         ));
     }
 
+    /// `compute_split` must reject a 0-bps recipient even when the remaining
+    /// percentages still sum to 100%.
+    #[test]
+    fn test_zero_bps_recipient_rejected() {
+        use crate::{compute_split, SplitError};
+        use soroban_sdk::{testutils::Address as _, Address, Env, Vec as SorobanVec};
+
+        let env = Env::default();
+        let contract_id = env.register(DummyContract, ());
+        let a = Address::generate(&env);
+        let b = Address::generate(&env);
+        let recipients = SorobanVec::from_array(&env, [(a.clone(), 5_000u32), (b, 0u32), (a.clone(), 5_000u32)]);
+
+        let result = env.as_contract(&contract_id, || {
+            compute_split(&env, 1_000_000, 0, &recipients)
+        });
+        assert!(matches!(result, Err(SplitError::InvalidSplit)));
+    }
+
+    /// Duplicate recipient addresses are invalid because they create multiple
+    /// transfers to the same address and distort indexer accounting.
+    #[test]
+    fn test_duplicate_recipients_rejected() {
+        use crate::{compute_split, SplitError};
+        use soroban_sdk::{testutils::Address as _, Address, Env, Vec as SorobanVec};
+
+        let env = Env::default();
+        let contract_id = env.register(DummyContract, ());
+        let recipient = Address::generate(&env);
+        let recipients = SorobanVec::from_array(&env, [(recipient.clone(), 5_000u32), (recipient, 5_000u32)]);
+
+        let result = env.as_contract(&contract_id, || {
+            compute_split(&env, 1_000_000, 0, &recipients)
+        });
+        assert!(matches!(result, Err(SplitError::InvalidSplit)));
+    }
+
     /// Sanity counterpart: the real `compute_split` accepts a single
     /// recipient at 100%, so the empty-list rejection above is specific to
     /// emptiness and not a blanket failure of the harness.
diff --git a/contracts/escrow/src/lib.rs b/contracts/escrow/src/lib.rs
index 64510d74..9d97b71e 100644
--- a/contracts/escrow/src/lib.rs
+++ b/contracts/escrow/src/lib.rs
@@ -989,6 +989,11 @@ mod contract {
             mergefi_common::get_fee_bps::<DataKey>(&env).ok_or(Error::NotInitialized)
         }
 
+        /// Admin-only: rotate the treasury address.
+        ///
+        /// Requires the current admin to authorize the change. The call rejects
+        /// an invalid treasury candidate (`InvalidTreasury`) and, once accepted,
+        /// routes all subsequent protocol-fee payouts to the updated treasury.
         pub fn set_treasury(env: Env, new_treasury: Address) -> Result<(), Error> {
             let admin = require_admin(&env)?;
             admin.require_auth();