diff --git a/reactos/lib/crt/stdlib/fullpath.c b/reactos/lib/crt/stdlib/fullpath.c
index 0ed77c88265..61d6d114c66 100644
--- a/reactos/lib/crt/stdlib/fullpath.c
+++ b/reactos/lib/crt/stdlib/fullpath.c
@@ -17,8 +17,16 @@
 _TCHAR* _tfullpath(_TCHAR* absPath, const _TCHAR* relPath, size_t maxLength)
 {
     _TCHAR* lpFilePart;
+    DWORD copied;
 
-    if (GetFullPathName(relPath,maxLength,absPath,&lpFilePart) == 0)
+    if (!absPath)
+    {
+        maxLength = MAX_PATH;
+        absPath = malloc(maxLength);
+    }
+
+    copied = GetFullPathName(relPath,maxLength,absPath,&lpFilePart);
+    if (copied == 0 || copied > maxLength)
         return NULL;
 
     return absPath;