diff --git a/pkgs/development/perl-modules/CryptDES-gcc14.patch b/pkgs/development/perl-modules/CryptDES-gcc14.patch
new file mode 100644
index 000000000000..10b161c247e2
--- /dev/null
+++ b/pkgs/development/perl-modules/CryptDES-gcc14.patch
@@ -0,0 +1,8 @@
+--- a/_des.h
++++ b/_des.h
+@@ -4,4 +4,6 @@
+ 
+ void _des_crypt( des_cblock in, des_cblock out, des_ks key, int encrypt );
+ void _des_expand_key( des_user_key userKey, des_ks key );
++void perl_des_expand_key( des_user_key userKey, des_ks key );
++void perl_des_crypt( des_cblock input, des_cblock output, des_ks ks, int encrypt );
diff --git a/pkgs/top-level/perl-packages.nix b/pkgs/top-level/perl-packages.nix
index 4403115a5edd..94923ff13f68 100644
--- a/pkgs/top-level/perl-packages.nix
+++ b/pkgs/top-level/perl-packages.nix
@@ -5018,6 +5018,10 @@ with self; {
       url = "mirror://cpan/authors/id/D/DP/DPARIS/Crypt-DES-2.07.tar.gz";
       hash = "sha256-LbHrtYN7TLIAUcDuW3M7RFPjE33wqSMGA0yGdiHt1+c=";
     };
+    patches = [
+      # add extra definitions in header to please -Werror=implicit-function-declaration
+      ../development/perl-modules/CryptDES-gcc14.patch
+    ];
     meta = {
       description = "Perl DES encryption module";
       license = with lib.licenses; [ bsdOriginalShortened ];