diff --git a/pkgs/by-name/de/deno/rusty-v8/default.nix b/pkgs/by-name/de/deno/rusty-v8/default.nix
index b781960359c1..725ecebed0b3 100644
--- a/pkgs/by-name/de/deno/rusty-v8/default.nix
+++ b/pkgs/by-name/de/deno/rusty-v8/default.nix
@@ -144,9 +144,14 @@ rustPlatform.buildRustPackage (finalAttrs: {
 
   buildFeatures = [ "simdutf" ];
 
-  # rusty-v8 has its own default hardening flags, which are "extensive" for release builds as long as `use_custom_libcxx` stays true.
-  # Avoids many warnings about redefined macros (on build failures) and uses the upstream flag.
-  hardeningDisable = [ "libcxxhardeningfast" ];
+  hardeningDisable = [
+    # rusty-v8 has its own default hardening flags, which are "extensive" for release builds as long as `use_custom_libcxx` stays true.
+    # Avoids many warnings about redefined macros (on build failures) and uses the upstream flag.
+    "libcxxhardeningfast"
+    # from Arch Linux: this uses malloc_usable_size, which is incompatible with fortification level 3
+    # https://gitlab.archlinux.org/archlinux/packaging/packages/deno/-/blob/cd9bdf9e67381da413142413646bd8648807510a/PKGBUILD#L49
+    "fortify3"
+  ];
 
   checkFlags = [
     # These tests probably fail due to a more recent rustc version (upstream: 1.89.0, here: 1.93.0)