diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## Version 2.0.1
+
+* Fix a leak of pending data to be sent.
+
 ## Version 2.0.0
 
 * `tls` now only supports TLS 1.2 and TLS 1.3 with safe cipher suites.
diff --git a/Network/TLS/Context/Internal.hs b/Network/TLS/Context/Internal.hs
--- a/Network/TLS/Context/Internal.hs
+++ b/Network/TLS/Context/Internal.hs
@@ -194,6 +194,7 @@
     , tls13stPendingRecvData :: Maybe ByteString -- client
     , tls13stPendingSentData :: [ByteString] -> [ByteString] -- client
     , tls13stRTT :: Millisecond
+    , tls13st0RTT :: Bool -- client
     , tls13st0RTTAccepted :: Bool -- client
     , tls13stClientExtensions :: [ExtensionRaw] -- client
     , tls13stChoice :: ~CipherChoice -- client
@@ -213,6 +214,7 @@
         , tls13stPendingRecvData = Nothing
         , tls13stPendingSentData = id
         , tls13stRTT = 0
+        , tls13st0RTT = False
         , tls13st0RTTAccepted = False
         , tls13stClientExtensions = []
         , tls13stChoice = undefined
diff --git a/Network/TLS/Core.hs b/Network/TLS/Core.hs
--- a/Network/TLS/Core.hs
+++ b/Network/TLS/Core.hs
@@ -69,9 +69,10 @@
     handshake_ ctx
     -- Trying to receive an alert of client authentication failure
     liftIO $ do
+        role <- usingState_ ctx getRole
         tls13 <- tls13orLater ctx
         sentClientCert <- tls13stSentClientCert <$> getTLS13State ctx
-        when (tls13 && sentClientCert) $ do
+        when (role == ClientRole && tls13 && sentClientCert) $ do
             rtt <- getRTT ctx
             mdat <- timeout rtt $ recvData ctx
             case mdat of
@@ -156,11 +157,13 @@
 sendData _ "" = return ()
 sendData ctx dataToSend = liftIO $ do
     tls13 <- tls13orLater ctx
-    sentCF <- tls13stSentCF <$> getTLS13State ctx
     let sendP bs
             | tls13 = do
                 sendPacket13 ctx $ AppData13 bs
-                unless sentCF $
+                role <- usingState_ ctx getRole
+                sentCF <- tls13stSentCF <$> getTLS13State ctx
+                rtt0 <- tls13st0RTT <$> getTLS13State ctx
+                when (role == ClientRole && rtt0 && not sentCF) $
                     modifyTLS13State ctx $
                         \st -> st{tls13stPendingSentData = tls13stPendingSentData st . (bs :)}
             | otherwise = sendPacket12 ctx $ AppData bs
diff --git a/Network/TLS/Handshake/Client.hs b/Network/TLS/Handshake/Client.hs
--- a/Network/TLS/Handshake/Client.hs
+++ b/Network/TLS/Handshake/Client.hs
@@ -62,6 +62,7 @@
     --------------------------------
     -- Sending ClientHello
     pskinfo@(_, _, rtt0) <- getPreSharedKeyInfo cparams ctx
+    when rtt0 $ modifyTLS13State ctx $ \st -> st{tls13st0RTT = True}
     let async = rtt0 && not (ctxQUICMode ctx)
     when async $ do
         chSentTime <- getCurrentTimeFromBase
diff --git a/Network/TLS/Handshake/Client/TLS13.hs b/Network/TLS/Handshake/Client/TLS13.hs
--- a/Network/TLS/Handshake/Client/TLS13.hs
+++ b/Network/TLS/Handshake/Client/TLS13.hs
@@ -278,11 +278,13 @@
     contextSync ctx $ SendClientFinished eexts appSecInfo
     modifyTLS13State ctx $ \st -> st{tls13stHsKey = Nothing}
     handshakeDone13 ctx
-    builder <- tls13stPendingSentData <$> getTLS13State ctx
-    modifyTLS13State ctx $ \st -> st{tls13stPendingSentData = id}
-    unless rtt0accepted $
-        mapM_ (sendPacket13 ctx . AppData13) $
-            builder []
+    rtt0 <- tls13st0RTT <$> getTLS13State ctx
+    when rtt0 $ do
+        builder <- tls13stPendingSentData <$> getTLS13State ctx
+        modifyTLS13State ctx $ \st -> st{tls13stPendingSentData = id}
+        unless rtt0accepted $
+            mapM_ (sendPacket13 ctx . AppData13) $
+                builder []
   where
     usedCipher = cCipher choice
     usedHash = cHash choice
diff --git a/tls.cabal b/tls.cabal
--- a/tls.cabal
+++ b/tls.cabal
@@ -1,6 +1,6 @@
 cabal-version:      >=1.10
 name:               tls
-version:            2.0.0
+version:            2.0.1
 license:            BSD3
 license-file:       LICENSE
 copyright:          Vincent Hanquez <vincent@snarc.org>