diff --git a/local/patches/registry.json b/local/patches/registry.json
index 7a197d7..e53f1c9 100644
--- a/local/patches/registry.json
+++ b/local/patches/registry.json
@@ -18,5 +18,17 @@
     "makevars": {},
     "patch": "fs/force-vendored-libuv.patch",
     "reason": "fs 2.x configure links system libuv whenever pkg-config finds libuv-devel (installed as a build-time sysreq), producing an fs.so with NEEDED libuv.so.1. That binary fails to dyn.load on consumer machines lacking runtime libuv, because install.packages/renv do not install SystemRequirements (only pak does, and only in the build container). The patch short-circuits configure to copy src/Makevars.vendor and build the bundled static libuv (needs cmake) so the binary is self-contained on every platform. An env/pkg-config override was tried first but the rebuilt binary still linked libuv.so.1, so a source patch is used instead."
+  },
+  {
+    "package": "rstan",
+    "versions": "*",
+    "platforms": ["*"],
+    "env": {},
+    "configure_args": [],
+    "makevars": {
+      "CPPFLAGS": "-DTBB_INTERFACE_NEW -I/usr/local/include"
+    },
+    "patch": null,
+    "reason": "StanHeaders' init_threadpool_tbb.hpp unconditionally includes the legacy <tbb/tbb_stddef.h> (removed in oneTBB 2021+) for version detection, breaking compilation of Module.cpp against the bundled oneTBB. Pre-defining TBB_INTERFACE_NEW skips that include and selects the modern tbb/global_control.h + tbb/task_arena.h path that the bundled TBB provides (-I/usr/local/include preserves the default CPPFLAGS the override replaces)"
   }
 ]