# UNDF: UNDF-2026-000000162
--- a/server/channels/app/role.go
+++ b/server/channels/app/role.go
@@ -258,16 +258,12 @@ func (a *App) CheckRolesExist(roleNames []string) *model.AppError {
 		return err
 	}

-	for _, name := range roleNames {
-		nameFound := false
-		for _, role := range roles {
-			if name == role.Name {
-				nameFound = true
-				break
-			}
-		}
-		if !nameFound {
-			return model.NewAppError("CheckRolesExist", "app.role.check_roles_exist.role_not_found", nil, "role="+name, http.StatusBadRequest)
-		}
+	roleSet := make(map[string]bool, len(roles))
+	for _, role := range roles {
+		roleSet[role.Name] = true
+	}
+	for _, name := range roleNames {
+		if !roleSet[name] {
+			return model.NewAppError("CheckRolesExist", "app.role.check_roles_exist.role_not_found", nil, "role="+name, http.StatusBadRequest)
+		}
 	}

 	return nil