diff --git a/ouroboros-network/CHANGELOG.md b/ouroboros-network/CHANGELOG.md
index 148dd7439a..28b2f17f78 100644
--- a/ouroboros-network/CHANGELOG.md
+++ b/ouroboros-network/CHANGELOG.md
@@ -23,6 +23,9 @@
 * Added `daMinBigLedgerPeersForTrustedState` to `ArgumentsExtra` when starting diffusion.
   It is used by `outboundConnectionsState` when signaling trust state when syncing in
   Genesis mode. Default value is provided by the Configuration module.
+* `txSubmissionInbound` takes an additional callback which exposes
+  CBOR-encoded transaction size as it is when transmitted over the
+  network, except for some top level wrapping (cf. PR#4926 description)
 
 ### Non-Breaking changes
 
diff --git a/ouroboros-network/src/Ouroboros/Network/TxSubmission/Inbound.hs b/ouroboros-network/src/Ouroboros/Network/TxSubmission/Inbound.hs
index 36f804938d..2e480dd602 100644
--- a/ouroboros-network/src/Ouroboros/Network/TxSubmission/Inbound.hs
+++ b/ouroboros-network/src/Ouroboros/Network/TxSubmission/Inbound.hs
@@ -44,6 +44,7 @@ import Network.TypedProtocol.Pipelined (N, Nat (..), natToInt)
 import Ouroboros.Network.NodeToNode.Version (NodeToNodeVersion)
 import Ouroboros.Network.Protocol.Limits
 import Ouroboros.Network.Protocol.TxSubmission2.Server
+import Ouroboros.Network.SizeInBytes
 import Ouroboros.Network.Protocol.TxSubmission2.Type
 import Ouroboros.Network.TxSubmission.Inbound.Types (ProcessedTxCount (..),
            TraceTxSubmissionInbound (..), TxSubmissionMempoolWriter (..),
@@ -135,9 +136,10 @@ txSubmissionInbound
   -> NumTxIdsToAck  -- ^ Maximum number of unacknowledged txids allowed
   -> TxSubmissionMempoolReader txid tx idx m
   -> TxSubmissionMempoolWriter txid tx idx m
+  -> (tx -> SizeInBytes) -- ^ get size of CBOR encoded transaction
   -> NodeToNodeVersion
   -> TxSubmissionServerPipelined txid tx m ()
-txSubmissionInbound tracer (NumTxIdsToAck maxUnacked) mpReader mpWriter _version =
+txSubmissionInbound tracer (NumTxIdsToAck maxUnacked) mpReader mpWriter txSize _version =
     TxSubmissionServerPipelined $ do
 #ifdef TXSUBMISSION_DELAY
       -- make the client linger before asking for tx's and expending
@@ -262,8 +264,14 @@ txSubmissionInbound tracer (NumTxIdsToAck maxUnacked) mpReader mpWriter _version
         -- for. We should never get a tx we did not ask for. We take a strict
         -- approach to this and check it.
         --
-        let txsMap :: Map txid tx
-            txsMap = Map.fromList [ (txId tx, tx) | tx <- txs ]
+        let availableTxidsMap = availableTxids st
+            txsMap :: Map txid tx
+            txsMap = Map.fromList [ (txId', assert sizesMatch tx)
+                                  | tx <- txs
+                                  , let txId' = txId tx
+                                        calcSize = Just $ txSize tx
+                                        advertisedSize = availableTxidsMap Map.!? txId'
+                                        sizesMatch = calcSize == advertisedSize]
 
             txidsReceived  = Map.keysSet txsMap
             txidsRequested = Set.fromList txids
diff --git a/ouroboros-network/src/Ouroboros/Network/TxSubmission/Outbound.hs b/ouroboros-network/src/Ouroboros/Network/TxSubmission/Outbound.hs
index 29814d78e2..8c913baffb 100644
--- a/ouroboros-network/src/Ouroboros/Network/TxSubmission/Outbound.hs
+++ b/ouroboros-network/src/Ouroboros/Network/TxSubmission/Outbound.hs
@@ -27,6 +27,7 @@ import Ouroboros.Network.ControlMessage (ControlMessage, ControlMessageSTM,
            timeoutWithControlMessage)
 import Ouroboros.Network.NodeToNode.Version (NodeToNodeVersion)
 import Ouroboros.Network.Protocol.TxSubmission2.Client
+import Ouroboros.Network.SizeInBytes
 import Ouroboros.Network.Protocol.TxSubmission2.Type
 import Ouroboros.Network.TxSubmission.Mempool.Reader (MempoolSnapshot (..),
            TxSubmissionMempoolReader (..))