diff --git a/pkgs/by-name/li/libunarr/package.nix b/pkgs/by-name/li/libunarr/package.nix
index 2ea5d3025a24..bb5d2e88092f 100644
--- a/pkgs/by-name/li/libunarr/package.nix
+++ b/pkgs/by-name/li/libunarr/package.nix
@@ -2,6 +2,7 @@
   lib,
   stdenv,
   fetchurl,
+  fetchpatch,
   cmake,
 }:
 
@@ -14,6 +15,16 @@ stdenv.mkDerivation rec {
     hash = "sha256-Mo76BOqZbdOJFrEkeozxdqwpuFyvkhdONNMZmN5BdNI=";
   };
 
+  patches = [
+    # cmake-4 compatibility:
+    #   https://github.com/selmf/unarr/pull/30
+    (fetchpatch {
+      name = "cmake-4.patch";
+      url = "https://github.com/selmf/unarr/commit/1df8ab3d281409e9fe6bed8bf485976bb47f5bef.patch";
+      hash = "sha256-u3shRgtRcHYxvXAHmYyQH1HLYV1PgWaJBY7BZCOYiL4=";
+    })
+  ];
+
   postPatch = lib.optionalString stdenv.hostPlatform.isDarwin ''
     substituteInPlace CMakeLists.txt \
       --replace "-flto" "" \