diff --git a/test/fuzzing/named_arg.cpp b/test/fuzzing/named_arg.cpp
index 247f9495d418..ddd90d1c472b 100644
--- a/test/fuzzing/named_arg.cpp
+++ b/test/fuzzing/named_arg.cpp
@@ -33,7 +33,7 @@ void invoke_fmt(const uint8_t* Data, std::size_t Size, unsigned int argsize) {
   std::memcpy(argnamebuffer.data(), Data, argsize);
   auto argname = fmt::string_view(argnamebuffer.data(), argsize);
 #else
-  auto argname = fmt::string_view((const char*)Data, argsize);
+  auto argname = fmt::string_view(fmt_fuzzer::as_chars(Data), argsize);
 #endif
   Data += argsize;
   Size -= argsize;
@@ -44,7 +44,7 @@ void invoke_fmt(const uint8_t* Data, std::size_t Size, unsigned int argsize) {
   std::memcpy(fmtstringbuffer.data(), Data, Size);
   auto fmtstring = fmt::string_view(fmtstringbuffer.data(), Size);
 #else
-  auto fmtstring = fmt::string_view((const char*)Data, Size);
+  auto fmtstring = fmt::string_view(fmt_fuzzer::as_chars(Data), Size);
 #endif
   std::string message = fmt::format(fmtstring, fmt::arg(argname, item1));
 }
diff --git a/test/fuzzing/one_arg.cpp b/test/fuzzing/one_arg.cpp
index b45f25123305..70b06b9b59b5 100644
--- a/test/fuzzing/one_arg.cpp
+++ b/test/fuzzing/one_arg.cpp
@@ -29,7 +29,7 @@ void invoke_fmt(const uint8_t* Data, std::size_t Size) {
   std::memcpy(fmtstringbuffer.data(), Data, Size);
   auto fmtstring = fmt::string_view(fmtstringbuffer.data(), Size);
 #else
-  auto fmtstring = fmt::string_view((const char*)Data, Size);
+  auto fmtstring = fmt::string_view(fmt_fuzzer::as_chars(Data), Size);
 #endif
 
 #if FMT_FUZZ_FORMAT_TO_STRING
@@ -56,7 +56,7 @@ void invoke_fmt_time(const uint8_t* Data, std::size_t Size) {
   std::memcpy(fmtstringbuffer.data(), Data, Size);
   auto fmtstring = fmt::string_view(fmtstringbuffer.data(), Size);
 #else
-  auto fmtstring = fmt::string_view((const char*)Data, Size);
+  auto fmtstring = fmt::string_view(fmt_fuzzer::as_chars(Data), Size);
 #endif
   auto* b = std::localtime(&item);
   if (b) {