diff --git a/CMakeLists.txt b/CMakeLists.txt
index 22f1022a54..b66756521c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -141,11 +141,7 @@ endif(WIN32)
 
 # set a few other things at the top level to prevent incompatibilities
 set(CMAKE_C_STANDARD 99)
-if(NOT CRYPTO_BACKEND_BOTAN3)
-  set(CMAKE_CXX_STANDARD 11)
-else()
-  set(CMAKE_CXX_STANDARD 20)
-endif()
+set(CMAKE_CXX_STANDARD 11)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
 add_definitions(-D_GNU_SOURCE)
diff --git a/cmake/Modules/FindBotan.cmake b/cmake/Modules/FindBotan.cmake
index 1babefca2e..abdfe2b38f 100644
--- a/cmake/Modules/FindBotan.cmake
+++ b/cmake/Modules/FindBotan.cmake
@@ -84,14 +84,21 @@ if(DEFINED ENV{BOTAN_ROOT_DIR})
   list(APPEND _hints_lib "$ENV{BOTAN_ROOT_DIR}/lib")
 endif()
 
+# Append PC_* stuff only if BOTAN_ROOT_DIR is not specified
+if(NOT _hints_include)
+  list(APPEND _hints_include ${PC_BOTAN_INCLUDEDIR} ${PC_BOTAN_INCLUDE_DIRS})
+  list(APPEND _hints_lib ${PC_BOTAN_LIBDIR} ${PC_BOTAN_LIBRARY_DIRS})
+else()
+  set(_no_def_path "NO_DEFAULT_PATH")
+endif()
+
 # find the headers
 find_path(BOTAN_INCLUDE_DIR
   NAMES botan/version.h
   HINTS
     ${_hints_include}
-    ${PC_BOTAN_INCLUDEDIR}
-    ${PC_BOTAN_INCLUDE_DIRS}
   PATH_SUFFIXES ${_suffixes}
+  ${_no_def_path}
 )
 
 # find the library
@@ -100,8 +107,7 @@ if(MSVC)
     NAMES botan
     HINTS
       ${_hints_lib}
-      ${PC_BOTAN_LIBDIR}
-      ${PC_BOTAN_LIBRARY_DIRS}
+    ${_no_def_path}
   )
 else()
   find_library(BOTAN_LIBRARY
@@ -109,15 +115,12 @@ else()
       ${_names}
     HINTS
       ${_hints_lib}
-      ${PC_BOTAN_LIBDIR}
-      ${PC_BOTAN_LIBRARY_DIRS}
+    ${_no_def_path}
   )
 endif()
 
 # determine the version
-if(PC_BOTAN_VERSION)
-    set(BOTAN_VERSION ${PC_BOTAN_VERSION})
-elseif(BOTAN_INCLUDE_DIR AND EXISTS "${BOTAN_INCLUDE_DIR}/botan/build.h")
+if(BOTAN_INCLUDE_DIR AND EXISTS "${BOTAN_INCLUDE_DIR}/botan/build.h")
     file(STRINGS "${BOTAN_INCLUDE_DIR}/botan/build.h" botan_version_str
       REGEX "^#define[\t ]+(BOTAN_VERSION_[A-Z]+)[\t ]+[0-9]+")
 
@@ -163,4 +166,3 @@ if (BOTAN_FOUND AND NOT TARGET Botan::Botan)
 endif()
 
 mark_as_advanced(BOTAN_INCLUDE_DIR BOTAN_LIBRARY)
-
diff --git a/src/lib/CMakeLists.txt b/src/lib/CMakeLists.txt
index c8fbdcd1b8..fe6c7ff1c0 100755
--- a/src/lib/CMakeLists.txt
+++ b/src/lib/CMakeLists.txt
@@ -48,6 +48,10 @@ if (CRYPTO_BACKEND_OPENSSL)
   endif()
 endif()
 
+if(CRYPTO_BACKEND_BOTAN3)
+  set(CMAKE_CXX_STANDARD 20)
+endif()
+
 # generate a config.h
 include(CheckIncludeFileCXX)
 include(CheckCXXSymbolExists)
diff --git a/src/tests/CMakeLists.txt b/src/tests/CMakeLists.txt
index 026dc09750..502d0f6302 100644
--- a/src/tests/CMakeLists.txt
+++ b/src/tests/CMakeLists.txt
@@ -70,11 +70,18 @@ if (CRYPTO_BACKEND_BOTAN3)
   find_package(Botan 3.0.0 REQUIRED)
 elseif (CRYPTO_BACKEND_BOTAN)
   find_package(Botan 2.14.0 REQUIRED)
+  if(BOTAN_VERSION VERSION_GREATER_EQUAL 3.0.0)
+    set(CRYPTO_BACKEND_BOTAN3 1)
+  endif()
 endif()
 if (CRYPTO_BACKEND_LOWERCASE STREQUAL "openssl")
   find_package(OpenSSL 1.1.1 REQUIRED)
 endif()
 
+if(CRYPTO_BACKEND_BOTAN3)
+  set(CMAKE_CXX_STANDARD 20)
+endif()
+
 add_executable(rnp_tests
   ../rnp/rnpcfg.cpp
   ../rnp/fficli.cpp