diff --git a/pkgs/development/cuda-modules/packages/cuda_crt.nix b/pkgs/development/cuda-modules/packages/cuda_crt.nix
index 3cf2246235bd8..914967d7cc8d1 100644
--- a/pkgs/development/cuda-modules/packages/cuda_crt.nix
+++ b/pkgs/development/cuda-modules/packages/cuda_crt.nix
@@ -1,10 +1,39 @@
-{ backendStdenv, buildRedist }:
+{
+  lib,
+  backendStdenv,
+  buildRedist,
+  glibc,
+}:
 buildRedist {
   redistName = "cuda";
   pname = "cuda_crt";
 
   outputs = [ "out" ];
 
+  # Fix compatibility with glibc 2.42:
+  # CUDA >= 13.0 fixed sinpi/cospi (using __NV_IEC_60559_FUNCS_EXCEPTION_SPECIFIER), but
+  # rsqrt/rsqrtf in math_functions.h still lack noexcept, conflicting with glibc 2.42's
+  # declarations.
+  postInstall = lib.optionalString (lib.versionAtLeast glibc.version "2.42") ''
+    nixLog "Patching math_functions.h rsqrt signatures to match glibc's ones"
+    substituteInPlace "''${!outputInclude:?}/include/crt/math_functions.h" \
+      --replace-fail \
+        "rsqrt(double x);" \
+        "rsqrt(double x) noexcept (true);" \
+      --replace-fail \
+        "rsqrtf(float x);" \
+        "rsqrtf(float x) noexcept (true);"
+
+    nixLog "Patching math_functions.hpp rsqrt signatures to match glibc's ones"
+    substituteInPlace "''${!outputInclude:?}/include/crt/math_functions.hpp" \
+      --replace-fail \
+        "__func__(double rsqrt(const double a))" \
+        "__func__(double rsqrt(const double a) throw())" \
+      --replace-fail \
+        "__func__(float rsqrtf(const float a))" \
+        "__func__(float rsqrtf(const float a) throw())"
+  '';
+
   brokenAssertions = [
     # TODO(@connorbaker): Build fails on x86 when using pkgsLLVM.
     #  .../include/crt/host_defines.h:67:2:
diff --git a/pkgs/development/cuda-modules/packages/cuda_nvcc.nix b/pkgs/development/cuda-modules/packages/cuda_nvcc.nix
index 404811ffa2f5a..2bb34f2cf84f3 100644
--- a/pkgs/development/cuda-modules/packages/cuda_nvcc.nix
+++ b/pkgs/development/cuda-modules/packages/cuda_nvcc.nix
@@ -168,6 +168,11 @@ buildRedist (finalAttrs: {
       # The cospi|sinpi|rsqrt function signatures in include/common/math_functions.h do not match
       # glibc 2.42's.
       # Indeed, there they are declared with noexcept(true) which is not the case in cuda_nvcc.
+      # - In CUDA < 13.0, sinpi/cospi/rsqrt all lack exception specifiers.
+      # - In CUDA >= 13.0, NVIDIA fixed sinpi/cospi (using __NV_IEC_60559_FUNCS_EXCEPTION_SPECIFIER)
+      #   but rsqrt/rsqrtf still lack noexcept, so we only patch those.
+      #   As the CRT headers (including math_functions.h) moved to the cuda_crt package, the glibc
+      #   2.42 compatibility patch is applied there instead.
       + lib.optionalString (cudaOlder "13.0" && lib.versionAtLeast glibc.version "2.42") ''
         nixLog "Patching math_functions.h signatures to match glibc's ones"
         substituteInPlace "''${!outputInclude:?}/include/crt/math_functions.h" \
@@ -213,6 +218,7 @@ buildRedist (finalAttrs: {
             "__func__(float cospif(const float a))" \
             "__func__(float cospif(const float a) throw())"
       ''
+
       # Fix clang CUDA compilation: host_defines.h redefines __noinline__ as
       # __attribute__((noinline)), which conflicts with libstdc++ >=12 using
       # __attribute__((__noinline__)) — the macro expands to
diff --git a/pkgs/development/python-modules/deep-ep/default.nix b/pkgs/development/python-modules/deep-ep/default.nix
index 38309a06f9885..0ad6abb30b535 100644
--- a/pkgs/development/python-modules/deep-ep/default.nix
+++ b/pkgs/development/python-modules/deep-ep/default.nix
@@ -8,7 +8,6 @@
   setuptools,
 
   # env
-  symlinkJoin,
   cudaPackages,
 
   # buildInputs
@@ -20,11 +19,6 @@
   cudaSupport ? config.cudaSupport,
 }:
 let
-  inherit (lib)
-    getBin
-    getInclude
-    ;
-
   minSupportedCudaCapability = "8.0"; # build fails with 7.5
 
   minCudaCapability = builtins.head (
@@ -66,31 +60,34 @@ buildPythonPackage.override { inherit (torch) stdenv; } (finalAttrs: {
 
       DISABLE_SM90_FEATURES = if disableSm90Features then "1" else "0";
 
-      CUDA_HOME = symlinkJoin {
-        name = "cuda-redist";
-        paths = with cudaPackages; [
-          (getBin cuda_nvcc)
-
-          (getInclude cuda_cccl) # <nv/target>
-          (getInclude cuda_cudart) # cuda_runtime.h
-          (getInclude libcublas) # cublas_v2.h
-          (getInclude libcusolver) # cusolverDn.h
-          (getInclude libcusparse) # cusparse.h
-        ];
-      };
+      CUDA_HOME = (lib.getBin cudaPackages.cuda_nvcc).outPath;
     }
 
     # nvshmem must be disabled (unsetting NVSHMEM_DIR) when supporting <9.0 capabilities
     # https://github.com/deepseek-ai/DeepEP/blob/v1.2.1/setup.py#L65
     // lib.optionalAttrs (!disableSm90Features) {
-      NVSHMEM_DIR = (getInclude cudaPackages.libnvshmem).outPath;
+      NVSHMEM_DIR = (lib.getInclude cudaPackages.libnvshmem).outPath;
     }
   );
 
   buildInputs = [
     pybind11
     rdma-core
-  ];
+  ]
+  ++ lib.optionals cudaSupport (
+    with cudaPackages;
+    [
+      cuda_cccl # <nv/target>
+      cuda_cudart # cuda_runtime.h
+      libcublas # cublas_v2.h
+      libcusolver # cusolverDn.h
+      libcusparse # cusparse.h
+    ]
+    # On CUDA >=13.0, crt/host_config.h is shipped in cudaPackages.cuda_crt
+    ++ lib.optionals cuda_crt.meta.available [
+      cuda_crt # crt/host_config.h
+    ]
+  );
 
   pythonImportsCheck = [ "deep_ep" ];