diff --git a/lisp/emacs-lisp/find-func.el b/lisp/emacs-lisp/find-func.el
index 8f488a9c00a..6bdfb4bc38b 100644
--- a/lisp/emacs-lisp/find-func.el
+++ b/lisp/emacs-lisp/find-func.el
@@ -487,11 +487,14 @@ The search is done in the source for library LIBRARY."
                 ;; If the regexp search didn't find the location of
                 ;; the symbol (for example, because it is generated by
                 ;; a macro), try a slightly more expensive search that
-                ;; expands macros until it finds the symbol.
+                ;; expands macros until it finds the symbol.  Since
+                ;; macro-expansion involves arbitrary code execution,
+                ;; only attempt it in trusted buffers.
                 (cons (current-buffer)
-                      (find-function--search-by-expanding-macros
-                       (current-buffer) symbol type
-                       form-matcher-factory))))))))))
+                      (when (trusted-content-p)
+                        (find-function--search-by-expanding-macros
+                         (current-buffer) symbol type
+                         form-matcher-factory)))))))))))
 
 ;;;###autoload
 (defun find-function-update-type-alist (symbol type variable)