ladybird: mark vulnerable to CVE-2026-58592

Does not look like it was fixed upstream.
We also appears to be missing proper maintenance within nixpkgs,
the last update has not been backported to 26.05.

Closes #538210

pkgs/by-name/la/ladybird/package.nix

@@ -220,5 +220,8 @@ stdenv.mkDerivation (finalAttrs: {
     ];
     mainProgram = "Ladybird";
     broken = stdenv.hostPlatform.isDarwin;
+    knownVulnerabilities = [
+      "CVE-2026-58592"
+    ];
   };
 })