diff --git a/.gitlab/ci/configure_fedora40_common_clang.cmake b/.gitlab/ci/configure_fedora40_common_clang.cmake
index 9fdc6bc0f9..a4ae3f3f30 100644
--- a/.gitlab/ci/configure_fedora40_common_clang.cmake
+++ b/.gitlab/ci/configure_fedora40_common_clang.cmake
@@ -2,6 +2,9 @@ set(CMAKE_Fortran_COMPILER "/usr/bin/flang-new" CACHE FILEPATH "")
 set(CMAKE_Fortran_COMPILER_ID "LLVMFlang" CACHE STRING "")
 set(CMAKE_Fortran_COMPILER_SUPPORTS_F90 "1" CACHE BOOL "")
 
+set(CMake_TEST_C_STANDARDS "90;99;11;17;23" CACHE STRING "")
+set(CMake_TEST_CXX_STANDARDS "98;11;14;17;20;23;26" CACHE STRING "")
+
 set(CMake_TEST_FindOpenACC "ON" CACHE BOOL "")
 set(CMake_TEST_FindOpenACC_C "ON" CACHE BOOL "")
 set(CMake_TEST_FindOpenACC_CXX "ON" CACHE BOOL "")
diff --git a/.gitlab/ci/configure_fedora40_makefiles.cmake b/.gitlab/ci/configure_fedora40_makefiles.cmake
index 8b2373cdc5..478ba11c6b 100644
--- a/.gitlab/ci/configure_fedora40_makefiles.cmake
+++ b/.gitlab/ci/configure_fedora40_makefiles.cmake
@@ -1,5 +1,5 @@
 set(CMake_TEST_C_STANDARDS "90;99;11;17;23" CACHE STRING "")
-set(CMake_TEST_CXX_STANDARDS "98;11;14;17;20;23" CACHE STRING "")
+set(CMake_TEST_CXX_STANDARDS "98;11;14;17;20;23;26" CACHE STRING "")
 
 set(CMake_TEST_CTestUpdate_BZR "ON" CACHE BOOL "")
 set(CMake_TEST_CTestUpdate_GIT "ON" CACHE BOOL "")