From 7a19d2e7a48ffc7a6b16889adad63b121e98d82c Mon Sep 17 00:00:00 2001
From: Deniz Onur Duzgun <59659739+dduzgun-security@users.noreply.github.com>
Date: Fri, 14 Jun 2024 11:03:10 -0400
Subject: [PATCH] security: fix AliasCheck panic (#21339)

* security: fix AliasCheck panic

* add changelog
---
 .changelog/21339.txt  | 3 +++
 agent/checks/alias.go | 3 +++
 2 files changed, 6 insertions(+)
 create mode 100644 .changelog/21339.txt

diff --git a/.changelog/21339.txt b/.changelog/21339.txt
new file mode 100644
index 0000000000..8e8379ada0
--- /dev/null
+++ b/.changelog/21339.txt
@@ -0,0 +1,3 @@
+```release-note:bug
+core: Fix panic runtime error on AliasCheck
+```
diff --git a/agent/checks/alias.go b/agent/checks/alias.go
index f75c05b958..3b0226b9f4 100644
--- a/agent/checks/alias.go
+++ b/agent/checks/alias.go
@@ -144,6 +144,9 @@ func (c *CheckAlias) runLocal(stopCh chan struct{}) {
 type CheckIfServiceIDExists func(*structs.ServiceID) bool
 
 func (c *CheckAlias) checkServiceExistsOnRemoteServer(serviceID *structs.ServiceID) (bool, error) {
+	if serviceID == nil {
+		return false, fmt.Errorf("serviceID cannot be nil")
+	}
 	args := c.RPCReq
 	args.Node = c.Node
 	args.AllowStale = true