diff --git a/src/libxrpl/protocol/STTx.cpp b/src/libxrpl/protocol/STTx.cpp
index cd2da12316..0092916ddc 100644
--- a/src/libxrpl/protocol/STTx.cpp
+++ b/src/libxrpl/protocol/STTx.cpp
@@ -296,6 +296,14 @@ STTx::checkBatchSign(Rules const& rules) const
         if (!isFieldPresent(sfBatchSigners))
             return std::unexpected("Missing BatchSigners field.");  // LCOV_EXCL_LINE
         STArray const& signers{getFieldArray(sfBatchSigners)};
+        // Bound signature verification to the protocol cap. This runs in
+        // checkValidity (via checkSign) at relay / submit time, BEFORE preflight
+        // and passesLocalChecks enforce the cap. Without this guard a malicious
+        // peer could put an oversized sfBatchSigners array in a 1 MB blob and
+        // force one signature verification per entry before any of those checks
+        // (or the fee charge) runs.
+        if (signers.size() > kMaxBatchSigners)
+            return std::unexpected("BatchSigners array exceeds max entries.");
         for (auto const& signer : signers)
         {
             Blob const& signingPubKey = signer.getFieldVL(sfSigningPubKey);
@@ -578,9 +586,19 @@ STTx::buildBatchTxnIds()
 
     auto const& raw = getFieldArray(sfRawTransactions);
 
-    // Seated for any batch with raw transactions. The count is validated in
-    // preflight and at the relay boundary, so build every id here; this keeps
-    // the invariant batchTxnIds_->size() == rawTransactions.size().
+    // Bound the eager hashing to the protocol cap. This runs in the STTx
+    // constructor, i.e. at parse time, BEFORE preflight / passesLocalChecks
+    // enforce the cap and BEFORE checkValidity's signature check. Without this
+    // guard a malicious peer could put an oversized sfRawTransactions array in
+    // a 1 MB blob and force hashing of every inner id at deserialization.
+    // Leaving batchTxnIds_ unseated (nullopt) makes checkSign skip batch-signer
+    // verification for the oversized batch, which is then dropped by the count
+    // checks in preflight / passesLocalChecks downstream.
+    if (raw.size() > kMaxBatchTxCount)
+        return;
+
+    // For an in-cap batch the ids are always fully built, preserving the
+    // invariant batchTxnIds_->size() == rawTransactions.size().
     auto& ids = batchTxnIds_.emplace();
     ids.reserve(raw.size());
     for (STObject const& rb : raw)
diff --git a/src/test/app/Batch_test.cpp b/src/test/app/Batch_test.cpp
index f9c156fe06..64ef4998b1 100644
--- a/src/test/app/Batch_test.cpp
+++ b/src/test/app/Batch_test.cpp
@@ -1544,6 +1544,16 @@ class Batch_test : public beast::unit_test::Suite
                 BEAST_EXPECT(!result.applied && result.ter == temARRAY_TOO_LARGE);
                 return result.applied;
             });
+
+            // Regression (eager parse-time hashing): the relay boundary
+            // (checkValidity) rejects the oversized inner array. buildBatchTxnIds
+            // leaves batchTxnIds_ unseated past kMaxBatchTxCount, so no inner ids
+            // are hashed and checkSign skips batch-signer crypto; the batch is
+            // dropped by the local checks instead.
+            auto const [valid, reason] = xrpl::checkValidity(
+                env.app().getHashRouter(), *jt.stx, env.current()->rules());
+            BEAST_EXPECT(valid == xrpl::Validity::SigGoodOnly);
+            BEAST_EXPECT(reason == "Raw Transactions array exceeds max entries.");
         }
 
         // Regression: the relay-boundary local check (isBatchRawTransactionOkay)
@@ -1598,6 +1608,14 @@ class Batch_test : public beast::unit_test::Suite
                 BEAST_EXPECT(!result.applied && result.ter == temARRAY_TOO_LARGE);
                 return result.applied;
             });
+
+            // Regression (uncapped batch-signer verification): the relay
+            // boundary (checkValidity) rejects the oversized signers array via
+            // the checkBatchSign guard, BEFORE verifying a single signature.
+            auto const [valid, reason] = xrpl::checkValidity(
+                env.app().getHashRouter(), *jt.stx, env.current()->rules());
+            BEAST_EXPECT(valid == xrpl::Validity::SigBad);
+            BEAST_EXPECT(reason == "BatchSigners array exceeds max entries.");
         }
     }