diff --git a/src/3rdparty/fmt/base.h b/src/3rdparty/fmt/base.h
index 0e867954bc..a76f42bf88 100644
--- a/src/3rdparty/fmt/base.h
+++ b/src/3rdparty/fmt/base.h
@@ -1719,7 +1719,7 @@ class format_string_checker {
 /// internal class and shouldn't be used directly, only via `memory_buffer`.
 template <typename T> class buffer {
  private:
-  T* ptr_;
+  T* ptr_ = nullptr;
   size_t size_;
   size_t capacity_;
 
diff --git a/src/3rdparty/fmt/chrono.h b/src/3rdparty/fmt/chrono.h
index 50c777c841..91f5bed840 100644
--- a/src/3rdparty/fmt/chrono.h
+++ b/src/3rdparty/fmt/chrono.h
@@ -538,7 +538,7 @@ FMT_BEGIN_EXPORT
 inline auto localtime(std::time_t time) -> std::tm {
   struct dispatcher {
     std::time_t time_;
-    std::tm tm_;
+    std::tm tm_{};
 
     inline dispatcher(std::time_t t) : time_(t) {}
 
@@ -589,7 +589,7 @@ inline auto localtime(std::chrono::local_time<Duration> time) -> std::tm {
 inline auto gmtime(std::time_t time) -> std::tm {
   struct dispatcher {
     std::time_t time_;
-    std::tm tm_;
+    std::tm tm_{};
 
     inline dispatcher(std::time_t t) : time_(t) {}