diff --git a/.changelog/15495.txt b/.changelog/15495.txt
new file mode 100644
index 00000000000..77b38170ce8
--- /dev/null
+++ b/.changelog/15495.txt
@@ -0,0 +1,3 @@
+```release-note:bug
+event stream: Fixed a bug where undefined ACL policies on the request's ACL would result in incorrect authentication errors
+```
diff --git a/nomad/stream/event_broker.go b/nomad/stream/event_broker.go
index 8ecf33ebded..93a5e7e30eb 100644
--- a/nomad/stream/event_broker.go
+++ b/nomad/stream/event_broker.go
@@ -301,9 +301,14 @@ func aclObjFromSnapshotForTokenSecretID(
 
 	for _, policyName := range aclToken.Policies {
 		policy, err := aclSnapshot.ACLPolicyByName(nil, policyName)
-		if err != nil || policy == nil {
+		if err != nil {
 			return nil, nil, errors.New("error finding acl policy")
 		}
+		if policy == nil {
+			// Ignore policies that don't exist, since they don't grant any
+			// more privilege.
+			continue
+		}
 		aclPolicies = append(aclPolicies, policy)
 	}
 
@@ -321,9 +326,14 @@ func aclObjFromSnapshotForTokenSecretID(
 
 		for _, policyLink := range role.Policies {
 			policy, err := aclSnapshot.ACLPolicyByName(nil, policyLink.Name)
-			if err != nil || policy == nil {
+			if err != nil {
 				return nil, nil, errors.New("error finding acl policy")
 			}
+			if policy == nil {
+				// Ignore policies that don't exist, since they don't grant any
+				// more privilege.
+				continue
+			}
 			aclPolicies = append(aclPolicies, policy)
 		}
 	}