diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 0d2caf45b108..6685f2590614 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -6817,7 +6817,9 @@ let
 
   gpm = callPackage ../servers/gpm { };
 
-  gradm = callPackage ../os-specific/linux/gradm { };
+  gradm = callPackage ../os-specific/linux/gradm {
+    flex = flex_2_5_35;
+  };
 
   hdparm = callPackage ../os-specific/linux/hdparm { };