diff --git a/pkgs/by-name/x2/x265/package.nix b/pkgs/by-name/x2/x265/package.nix
index a7b00775e138..1dbf1ad936c8 100644
--- a/pkgs/by-name/x2/x265/package.nix
+++ b/pkgs/by-name/x2/x265/package.nix
@@ -5,6 +5,7 @@
   fetchurl,
   cmake,
   nasm,
+  fetchpatch,
   fetchpatch2,
 
   # NUMA support enabled by default on NUMA platforms:
@@ -58,6 +59,26 @@ stdenv.mkDerivation rec {
     # fix compilation with gcc15
     # https://bitbucket.org/multicoreware/x265_git/pull-requests/36
     ./gcc15-fixes.patch
+
+    # Fix the build with CMake 4.
+    (fetchpatch {
+      name = "x265-fix-cmake-4-1.patch";
+      url = "https://bitbucket.org/multicoreware/x265_git/commits/b354c009a60bcd6d7fc04014e200a1ee9c45c167/raw";
+      stripLen = 1;
+      hash = "sha256-kS+hYZb5dnIlNoZ8ABmNkLkPx+NqCPy+DonXktBzJAE=";
+    })
+    (fetchpatch {
+      name = "x265-fix-cmake-4-2.patch";
+      url = "https://bitbucket.org/multicoreware/x265_git/commits/51ae8e922bcc4586ad4710812072289af91492a8/raw";
+      stripLen = 1;
+      hash = "sha256-ZrpyfSnijUgdyVscW73K48iEXa9k85ftNaQdr0HWSYg=";
+    })
+    (fetchpatch {
+      name = "x265-fix-cmake-4-3.patch";
+      url = "https://bitbucket.org/multicoreware/x265_git/commits/78e5ac35c13c5cbccc5933083edceb0d3eaeaa21/raw";
+      stripLen = 1;
+      hash = "sha256-qEihgUKGEdthbKz67s+/hS/qdpzl+3tEB3gx2tarax4=";
+    })
   ]
   # TODO: remove after update to version 4.2
   ++ lib.optionals (stdenv.hostPlatform.isAarch32 && stdenv.hostPlatform.isLinux) [