diff --git a/pkgs/by-name/ca/calibre/package.nix b/pkgs/by-name/ca/calibre/package.nix
index b7a3af7b4a16..a706eff0e343 100644
--- a/pkgs/by-name/ca/calibre/package.nix
+++ b/pkgs/by-name/ca/calibre/package.nix
@@ -86,6 +86,15 @@ stdenv.mkDerivation (finalAttrs: {
         url = "https://github.com/kovidgoyal/calibre/commit/9484ea82c6ab226c18e6ca5aa000fa16de598726.patch";
         hash = "sha256-hpWFSQXyOAVRqou0v+5oT5zIrBbyP2Uv2z1Vg811ZG0=";
       })
+      # Fix CVE-2026-25731
+      # http://tracker.security.nixos.org/issues/NIXPKGS-2026-0155
+      # https://github.com/NixOS/nixpkgs/issues/488045
+      # Fixed upstream in 9.2.0.
+      (fetchpatch {
+        name = "CVE-2026-25731.patch";
+        url = "https://github.com/kovidgoyal/calibre/commit/f0649b27512e987b95fcab2e1e0a3bcdafc23379.patch";
+        hash = "sha256-G9H6hEN5cyFIqDmJZv+bgt+6ZF6/K2t9npYjksjcxTo=";
+      })
     ]
     ++ lib.optional (!unrarSupport) ./dont_build_unrar_plugin.patch;