diff --git a/src/win/util.c b/src/win/util.c
index c4dd8bf7..628136c4 100644
--- a/src/win/util.c
+++ b/src/win/util.c
@@ -942,8 +942,13 @@ int uv_os_homedir(char* buffer, size_t* size) {
   r = uv_os_getenv("USERPROFILE", buffer, size);
 
   /* Don't return an error if USERPROFILE was not found. */
-  if (r != UV_ENOENT)
+  if (r != UV_ENOENT) {
+    /* USERPROFILE is empty or invalid */
+    if (r == 0 && *size < 3) {
+      return UV_ENOENT;
+    }
     return r;
+  }
 
   /* USERPROFILE is not set, so call uv_os_get_passwd() */
   r = uv_os_get_passwd(&pwd);
@@ -980,6 +985,12 @@ int uv_os_tmpdir(char* buffer, size_t* size) {
   if (len == 0) {
     return uv_translate_sys_error(GetLastError());
   }
+
+  /* tmp path is empty or invalid */
+  if (len < 3) {
+    return UV_ENOENT;
+  }
+
   /* Include space for terminating null char. */
   len += 1;
   path = uv__malloc(len * sizeof(wchar_t));
diff --git a/test/test-homedir.c b/test/test-homedir.c
index 769d5c81..e335540d 100644
--- a/test/test-homedir.c
+++ b/test/test-homedir.c
@@ -68,5 +68,14 @@ TEST_IMPL(homedir) {
   r = uv_os_homedir(homedir, &len);
   ASSERT_EQ(r, UV_EINVAL);
 
+#ifdef _WIN32
+  /* Test empty environment variable */
+  r = uv_os_setenv("USERPROFILE", "");
+  ASSERT_EQ(r, 0);
+  len = sizeof homedir;
+  r = uv_os_homedir(homedir, &len);
+  ASSERT_EQ(r, UV_ENOENT);
+#endif
+
   return 0;
 }
diff --git a/test/test-tmpdir.c b/test/test-tmpdir.c
index a4e9ce95..c8fc8e06 100644
--- a/test/test-tmpdir.c
+++ b/test/test-tmpdir.c
@@ -76,6 +76,13 @@ TEST_IMPL(tmpdir) {
   size_t lenx = sizeof tmpdirx;
   r = uv_os_tmpdir(tmpdirx, &lenx);
   ASSERT_OK(r);
+
+  /* Test empty environment variable */
+  r = uv_os_setenv("TMP", "");
+  ASSERT_EQ(r, 0);
+  len = sizeof tmpdir;
+  r = uv_os_tmpdir(tmpdir, &len);
+  ASSERT_EQ(r, UV_ENOENT);
 #endif
 
   return 0;