diff --git a/federationapi/routing/leave.go b/federationapi/routing/leave.go
index 49c777124..636ade748 100644
--- a/federationapi/routing/leave.go
+++ b/federationapi/routing/leave.go
@@ -165,8 +165,32 @@ func SendLeave(
 		}
 	}
 
-	event, err := gomatrixserverlib.HandleSendLeave(
-		httpReq.Context(), request.Content(), request.Origin(), roomVersion, eventID, roomID, rsAPI, keys,
+	verImpl, err := gomatrixserverlib.GetRoomVersion(roomVersion)
+	if err != nil {
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: spec.UnsupportedRoomVersion(err.Error()),
+		}
+	}
+
+	// Decode the incomingEvent JSON from the request.
+	incomingEvent, err := verImpl.NewEventFromUntrustedJSON(request.Content())
+	switch err.(type) {
+	case gomatrixserverlib.BadJSONError:
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: spec.BadJSON(err.Error()),
+		}
+	case nil:
+	default:
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: spec.NotJSON("The request body could not be decoded into valid JSON. " + err.Error()),
+		}
+	}
+
+	leaveEvent, err := verImpl.HandleSendLeave(
+		httpReq.Context(), incomingEvent, request.Origin(), eventID, roomID, rsAPI, keys,
 	)
 
 	switch e := err.(type) {
@@ -211,7 +235,7 @@ func SendLeave(
 		InputRoomEvents: []api.InputRoomEvent{
 			{
 				Kind:          api.KindNew,
-				Event:         &types.HeaderedEvent{PDU: event},
+				Event:         &types.HeaderedEvent{PDU: leaveEvent},
 				SendAsServer:  string(cfg.Matrix.ServerName),
 				TransactionID: nil,
 			},
diff --git a/go.mod b/go.mod
index 8906b8c66..d206c91ed 100644
--- a/go.mod
+++ b/go.mod
@@ -22,7 +22,7 @@ require (
 	github.com/matrix-org/dugong v0.0.0-20210921133753-66e6b1c67e2e
 	github.com/matrix-org/go-sqlite3-js v0.0.0-20220419092513-28aa791a1c91
 	github.com/matrix-org/gomatrix v0.0.0-20220926102614-ceba4d9f7530
-	github.com/matrix-org/gomatrixserverlib v0.0.0-20230601112942-5d099f949e82
+	github.com/matrix-org/gomatrixserverlib v0.0.0-20230602105922-540062a7516d
 	github.com/matrix-org/pinecone v0.11.1-0.20230210171230-8c3b24f2649a
 	github.com/matrix-org/util v0.0.0-20221111132719-399730281e66
 	github.com/mattn/go-sqlite3 v1.14.16
diff --git a/go.sum b/go.sum
index 0060419f2..a551bc5a4 100644
--- a/go.sum
+++ b/go.sum
@@ -323,8 +323,8 @@ github.com/matrix-org/go-sqlite3-js v0.0.0-20220419092513-28aa791a1c91 h1:s7fexw
 github.com/matrix-org/go-sqlite3-js v0.0.0-20220419092513-28aa791a1c91/go.mod h1:e+cg2q7C7yE5QnAXgzo512tgFh1RbQLC0+jozuegKgo=
 github.com/matrix-org/gomatrix v0.0.0-20220926102614-ceba4d9f7530 h1:kHKxCOLcHH8r4Fzarl4+Y3K5hjothkVW5z7T1dUM11U=
 github.com/matrix-org/gomatrix v0.0.0-20220926102614-ceba4d9f7530/go.mod h1:/gBX06Kw0exX1HrwmoBibFA98yBk/jxKpGVeyQbff+s=
-github.com/matrix-org/gomatrixserverlib v0.0.0-20230601112942-5d099f949e82 h1:VC9MCGI47z3ksNQt/sTcnwO//syibxgyz/6ckD6BjkY=
-github.com/matrix-org/gomatrixserverlib v0.0.0-20230601112942-5d099f949e82/go.mod h1:H9V9N3Uqn1bBJqYJNGK1noqtgJTaCEhtTdcH/mp50uU=
+github.com/matrix-org/gomatrixserverlib v0.0.0-20230602105922-540062a7516d h1:7zP85gTIeoHb/GG0qRVi5uhwfnbSpt7G8SwDvGw7mUE=
+github.com/matrix-org/gomatrixserverlib v0.0.0-20230602105922-540062a7516d/go.mod h1:H9V9N3Uqn1bBJqYJNGK1noqtgJTaCEhtTdcH/mp50uU=
 github.com/matrix-org/pinecone v0.11.1-0.20230210171230-8c3b24f2649a h1:awrPDf9LEFySxTLKYBMCiObelNx/cBuv/wzllvCCH3A=
 github.com/matrix-org/pinecone v0.11.1-0.20230210171230-8c3b24f2649a/go.mod h1:HchJX9oKMXaT2xYFs0Ha/6Zs06mxLU8k6F1ODnrGkeQ=
 github.com/matrix-org/util v0.0.0-20221111132719-399730281e66 h1:6z4KxomXSIGWqhHcfzExgkH3Z3UkIXry4ibJS4Aqz2Y=