diff --git a/pkgs/by-name/ro/root5/package.nix b/pkgs/by-name/ro/root5/package.nix
index 0a03d44667d5..01fb35ee76d8 100644
--- a/pkgs/by-name/ro/root5/package.nix
+++ b/pkgs/by-name/ro/root5/package.nix
@@ -121,6 +121,11 @@ stdenv.mkDerivation rec {
       substituteInPlace misc/memstat/src/TMemStatHook.cxx \
         --replace "defined(R__GNU) && (defined(R__LINUX) || defined(__APPLE__))" \
                   "defined(R__GNU) && (defined(__APPLE__))"
+
+      # python 3.12
+      substituteInPlace bindings/pyroot/src/PyROOT.h \
+        --replace " PyUnicode_GET_SIZE" " PyUnicode_GetLength" \
+        --replace " PyUnicode_GetSize" " PyUnicode_GetLength"
     ''
     # Fix CINTSYSDIR for "build" version of rootcint
     # This is probably a bug that breaks out-of-source builds
@@ -169,6 +174,8 @@ stdenv.mkDerivation rec {
   ]
   ++ lib.optional ((!stdenv.hostPlatform.isDarwin) && (stdenv.cc.libc != null)) "-DC_INCLUDE_DIRS=${lib.getDev stdenv.cc.libc}/include";
 
+  env.NIX_CFLAGS_COMPILE = "-fpermissive";
+
   setupHook = ./setup-hook.sh;
 
   meta = with lib; {