diff --git a/libcxx/cmake/caches/Generic-cxx26.cmake b/libcxx/cmake/caches/Generic-cxx26.cmake
--- a/libcxx/cmake/caches/Generic-cxx26.cmake
+++ b/libcxx/cmake/caches/Generic-cxx26.cmake
@@ -1,2 +1,3 @@
+set(LIBCXX_ENABLE_STD_MODULES ON CACHE BOOL "") # TODO MODULES Remove when enabled automatically.
 set(LIBCXX_TEST_PARAMS "std=c++26" CACHE STRING "")
 set(LIBCXXABI_TEST_PARAMS "${LIBCXX_TEST_PARAMS}" CACHE STRING "")
diff --git a/libcxx/docs/Modules.rst b/libcxx/docs/Modules.rst
--- a/libcxx/docs/Modules.rst
+++ b/libcxx/docs/Modules.rst
@@ -49,12 +49,13 @@
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
  * There is no official build system support, libc++ has experimental CMake support
- * Requires CMake 3.26
+ * Requires CMake 3.26 for C++23 support
+ * Requires CMake 3.27 for C++26 support
  * Requires Ninja 1.11
  * Requires a recent Clang 17
  * The path to the compiler may not be a symlink, ``clang-scan-deps`` does
    not handle that case properly
- * Only C++23 is tested
+ * Only C++23 and C++26 are tested
  * Libc++ is not tested with modules instead of headers
  * The module ``.cppm`` files are not installed
  * The experimental ``PSTL`` library is not supported
diff --git a/libcxx/test/libcxx/module_std.gen.py b/libcxx/test/libcxx/module_std.gen.py
--- a/libcxx/test/libcxx/module_std.gen.py
+++ b/libcxx/test/libcxx/module_std.gen.py
@@ -127,7 +127,6 @@
     f"""\
 //--- module_std.sh.cpp
 // UNSUPPORTED{BLOCKLIT}: c++03, c++11, c++14, c++17, c++20
-// UNSUPPORTED{BLOCKLIT}: c++26
 // UNSUPPORTED{BLOCKLIT}: libcpp-has-no-std-modules
 // UNSUPPORTED{BLOCKLIT}: modules-build
 
diff --git a/libcxx/test/lit.local.cfg b/libcxx/test/lit.local.cfg
--- a/libcxx/test/lit.local.cfg
+++ b/libcxx/test/lit.local.cfg
@@ -31,11 +31,7 @@
 
 std = getSubstitution("%{cxx_std}", config)
 if std == "cxx26":
-    # This fails to work properly. It might be due to
-    #   CMAKE_CXX_STANDARD 26
-    # does not work in CMake 3.26, it requires the upcomming CMake 3.27.
-    # TODO MODULES test whether this is fixed with CMake 3.27.
-    std = ""
+    std = "26"
 elif std == "cxx23":
     std = "23"
 else:
diff --git a/libcxx/test/std/modules/std.pass.cpp b/libcxx/test/std/modules/std.pass.cpp
--- a/libcxx/test/std/modules/std.pass.cpp
+++ b/libcxx/test/std/modules/std.pass.cpp
@@ -7,8 +7,6 @@
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
-// TODO MODULES fix c++26
-// XFAIL: c++26
 
 // UNSUPPORTED: libcpp-has-no-std-modules
 // UNSUPPORTED: modules-build
diff --git a/libcxx/utils/ci/buildkite-pipeline.yml b/libcxx/utils/ci/buildkite-pipeline.yml
--- a/libcxx/utils/ci/buildkite-pipeline.yml
+++ b/libcxx/utils/ci/buildkite-pipeline.yml
@@ -116,8 +116,11 @@
       - "**/test-results.xml"
       - "**/*.abilist"
     env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
+        # Note modules require and absolute path for clang-scan-deps
+        # https://github.com/llvm/llvm-project/issues/61006
+        CC: "/usr/lib/llvm-${LLVM_HEAD_VERSION}/bin/clang"
+        CXX: "/usr/lib/llvm-${LLVM_HEAD_VERSION}/bin/clang++"
+        CMAKE: "/opt/bin/cmake"
         ENABLE_CLANG_TIDY: "On"
     agents:
       queue: "libcxx-builders"