diff --git a/config/cmake_ext_mod/CTestCustom.cmake b/config/cmake_ext_mod/CTestCustom.cmake
index 0111befbdb..f8d4cd60a3 100644
--- a/config/cmake_ext_mod/CTestCustom.cmake
+++ b/config/cmake_ext_mod/CTestCustom.cmake
@@ -4,6 +4,7 @@ set (CTEST_CUSTOM_WARNING_EXCEPTION
     ${CTEST_CUSTOM_WARNING_EXCEPTION}
     "note.*expected.*void.*but argument is of type.*volatile"
     "SZIP.src.*:[ \t]*warning"
+    "ZLIB.src.*:[ \t]*warning"
     "jpeg.src.*:[ \t]*warning"
     "POSIX name for this item is deprecated"
     "disabling jobserver mode"