diff --git a/cpp/cmake_modules/ThirdpartyToolchain.cmake b/cpp/cmake_modules/ThirdpartyToolchain.cmake
index d88e89ff021c8..a2627c190f738 100644
--- a/cpp/cmake_modules/ThirdpartyToolchain.cmake
+++ b/cpp/cmake_modules/ThirdpartyToolchain.cmake
@@ -446,8 +446,8 @@ endmacro()
 file(STRINGS "${THIRDPARTY_DIR}/versions.txt" TOOLCHAIN_VERSIONS_TXT)
 foreach(_VERSION_ENTRY ${TOOLCHAIN_VERSIONS_TXT})
   # Exclude comments
-  if(NOT ((_VERSION_ENTRY MATCHES "^[^ #][A-Za-z0-9-_]+_VERSION=")
-          OR (_VERSION_ENTRY MATCHES "^[^ #][A-Za-z0-9-_]+_CHECKSUM=")))
+  if(NOT ((_VERSION_ENTRY MATCHES "^[^#][A-Za-z0-9-_]+_VERSION=")
+          OR (_VERSION_ENTRY MATCHES "^[^#][A-Za-z0-9-_]+_CHECKSUM=")))
     continue()
   endif()