diff --git a/core/cli/doctor.el b/core/cli/doctor.el
index 1d838f844..e7e3fc4c5 100644
--- a/core/cli/doctor.el
+++ b/core/cli/doctor.el
@@ -62,7 +62,7 @@ in."
   (when EMACS27+
     (print! (start "Checking for great Emacs features..."))
     (unless (and (functionp 'json-serialize)
-                 (string-match-p "\\<_JSON\\_>" system-configuration-features))
+                 (string-match-p "\\_<JSON\\_>" system-configuration-features))
       (warn! "Emacs was not built with native JSON support")
       (explain! "Users will see a substantial performance gain by building Emacs with "
                 "jansson support (i.e. a native JSON library), particularly LSP users. "