diff --git a/pkgs/by-name/li/libcap_ng/package.nix b/pkgs/by-name/li/libcap_ng/package.nix
index da302c3cf49b..6662d8c99c3f 100644
--- a/pkgs/by-name/li/libcap_ng/package.nix
+++ b/pkgs/by-name/li/libcap_ng/package.nix
@@ -22,6 +22,8 @@ stdenv.mkDerivation (finalAttrs: {
   # NEWS needs to exist or else the build fails
   postPatch = ''
     touch NEWS
+    substituteInPlace utils/captest.c \
+      --replace-fail /usr/bin/captest ${placeholder "out"}/bin/captest
   '';
 
   strictDeps = true;