diff --git a/src/server/login.js b/src/server/login.js
index ec40ed913..a4a697ed2 100644
--- a/src/server/login.js
+++ b/src/server/login.js
@@ -184,7 +184,8 @@ module.exports = function (client, server, options) {
     client.write('success', {
       uuid: client.uuid,
       username: client.username,
-      properties: []
+      properties: [],
+      sessionId: crypto.randomUUID() // added to packet_success in 26.2 (protocol 776); ignored by protodef on older versions' schemas
     })
     if (client.supportFeature('hasConfigurationState')) {
       client.once('login_acknowledged', onClientLoginAck)