diff --git a/Auxiliary/cmake-mode.el b/Auxiliary/cmake-mode.el
index cf82d0971..11e33b378 100644
--- a/Auxiliary/cmake-mode.el
+++ b/Auxiliary/cmake-mode.el
@@ -200,7 +200,7 @@ the indentation.  Otherwise it retains the same position on the line"
      . font-lock-keyword-face)
     (,(rx symbol-start (group (+ (or word (syntax symbol)))) (* blank) ?\()
      1 font-lock-function-name-face)
-    ("\\${?\\([[:alpha:]_][[:alnum:]_]*\\|[0-9]+\\|[$*_]\\)"
+    (,(rx "${" (group (+(any alnum "-_+/."))) "}")
      1 font-lock-variable-name-face t)
     )
   "Highlighting expressions for CMake mode.")