From d9a80f952201e0f46f490a4f669c8f68c94d6fdc Mon Sep 17 00:00:00 2001
From: timedout <git@nexy7574.co.uk>
Date: Sun, 22 Feb 2026 18:37:22 +0000
Subject: [PATCH] federation/eventauth: Fix inverted membership check for 5.6.1

---
 federation/eventauth/eventauth.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/federation/eventauth/eventauth.go b/federation/eventauth/eventauth.go
index eac110a3..c72933c2 100644
--- a/federation/eventauth/eventauth.go
+++ b/federation/eventauth/eventauth.go
@@ -505,7 +505,7 @@ func authorizeMember(roomVersion id.RoomVersion, evt, createEvt *pdu.PDU, authEv
 		// 5.5.5. Otherwise, reject.
 		return ErrInsufficientPermissionForKick
 	case event.MembershipBan:
-		if senderMembership != event.MembershipLeave {
+		if senderMembership != event.MembershipJoin {
 			// 5.6.1. If the sender’s current membership state is not join, reject.
 			return ErrCantBanWithoutBeingInRoom
 		}