diff --git a/pkgs/servers/mail/opensmtpd/cross_fix.diff b/pkgs/servers/mail/opensmtpd/cross_fix.diff
new file mode 100644
index 000000000000..6f4c769954a9
--- /dev/null
+++ b/pkgs/servers/mail/opensmtpd/cross_fix.diff
@@ -0,0 +1,13 @@
+diff --git a/configure.ac b/configure.ac
+index c215f3bf..f5aa25d8 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -67,7 +67,7 @@ AC_C_BIGENDIAN
+ AC_PROG_CPP
+ AC_PROG_INSTALL
+ AC_PROG_LIBTOOL
+-AC_PATH_PROG([AR], [ar])
++AC_PATH_TOOL([AR], [ar])
+ AC_PATH_PROG([CAT], [cat])
+ AC_PATH_PROG([CHMOD], [chmod])
+ AC_PATH_PROG([CHOWN], [chown])
diff --git a/pkgs/servers/mail/opensmtpd/default.nix b/pkgs/servers/mail/opensmtpd/default.nix
index 72d4ca760e7e..5f36b139781b 100644
--- a/pkgs/servers/mail/opensmtpd/default.nix
+++ b/pkgs/servers/mail/opensmtpd/default.nix
@@ -16,6 +16,7 @@ stdenv.mkDerivation rec {
 
   patches = [
     ./proc_path.diff # TODO: upstream to OpenSMTPD, see https://github.com/NixOS/nixpkgs/issues/54045
+    ./cross_fix.diff # TODO: remove when https://github.com/OpenSMTPD/OpenSMTPD/pull/1177 will have made it into a release
   ];
 
   # See https://github.com/OpenSMTPD/OpenSMTPD/issues/885 for the `sh bootstrap`