diff --git a/src/xenia/base/string_buffer.cc b/src/xenia/base/string_buffer.cc
index 5bc3bad0a..90d386f23 100644
--- a/src/xenia/base/string_buffer.cc
+++ b/src/xenia/base/string_buffer.cc
@@ -12,13 +12,15 @@
 #include <algorithm>
 #include <cstdarg>
 
+#include "xenia/base/assert.h"
 #include "xenia/base/math.h"
 
 namespace xe {
 
 StringBuffer::StringBuffer(size_t initial_capacity) {
   buffer_capacity_ = std::max(initial_capacity, static_cast<size_t>(16 * 1024));
-  buffer_ = reinterpret_cast<char*>(malloc(buffer_capacity_));
+  buffer_ = reinterpret_cast<char*>(std::malloc(buffer_capacity_));
+  assert_not_null(buffer_);
   buffer_[0] = 0;
 }
 
@@ -40,7 +42,9 @@ void StringBuffer::Grow(size_t additional_length) {
   size_t new_capacity =
       std::max(xe::round_up(buffer_offset_ + additional_length, 16 * 1024),
                old_capacity * 2);
-  buffer_ = reinterpret_cast<char*>(realloc(buffer_, new_capacity));
+  auto new_buffer = std::realloc(buffer_, new_capacity);
+  assert_not_null(new_buffer);
+  buffer_ = reinterpret_cast<char*>(new_buffer);
   buffer_capacity_ = new_capacity;
 }
 
@@ -57,7 +61,11 @@ void StringBuffer::Append(const std::string_view value) {
 }
 
 void StringBuffer::AppendVarargs(const char* format, va_list args) {
-  int length = vsnprintf(nullptr, 0, format, args);
+  int result = vsnprintf(nullptr, 0, format, args);
+  if (result <= 0) {
+    return;
+  }
+  auto length = static_cast<size_t>(result);
   Grow(length + 1);
   vsnprintf(buffer_ + buffer_offset_, buffer_capacity_, format, args);
   buffer_offset_ += length;