From cdc3ef09e975767fb45d2fc1bcb4761b42b8be9b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bar=C4=B1=C5=9F=20Soner=20U=C5=9Fakl=C4=B1?=
 <baris@nodebb.org>
Date: Wed, 2 May 2018 13:49:08 -0400
Subject: [PATCH] closes #6481

---
 src/groups/create.js |  2 +-
 test/groups.js       | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/groups/create.js b/src/groups/create.js
index 9e0678a36f..46e8baff9d 100644
--- a/src/groups/create.js
+++ b/src/groups/create.js
@@ -91,7 +91,7 @@ module.exports = function (Groups) {
 			return callback(new Error('[[error:group-name-too-long]]'));
 		}
 
-		if (!Groups.isPrivilegeGroup(name) && name.includes(':')) {
+		if (name === 'guests' || (!Groups.isPrivilegeGroup(name) && name.includes(':'))) {
 			return callback(new Error('[[error:invalid-group-name]]'));
 		}
 
diff --git a/test/groups.js b/test/groups.js
index 5c54359203..fa81e33462 100644
--- a/test/groups.js
+++ b/test/groups.js
@@ -942,6 +942,16 @@ describe('Groups', function () {
 			});
 		});
 
+		it('should fail to create a group with name guests', function (done) {
+			var oldValue = meta.config.allowGroupCreation;
+			meta.config.allowGroupCreation = 1;
+			socketGroups.create({ uid: adminUid }, { name: 'guests' }, function (err) {
+				meta.config.allowGroupCreation = oldValue;
+				assert.equal(err.message, '[[error:invalid-group-name]]');
+				done();
+			});
+		});
+
 		it('should fail to rename guests group', function (done) {
 			var data = {
 				groupName: 'guests',