diff --git a/Lib/gzip.py b/Lib/gzip.py
index a2f2367..99b2d3e 100644
--- a/Lib/gzip.py
+++ b/Lib/gzip.py
@@ -202,7 +202,8 @@
 
         if flag & FEXTRA:
             # Read & discard the extra field, if present
-            self._read_exact(struct.unpack("<H", self._read_exact(2)))
+            extra_len, = struct.unpack("<H", self._read_exact(2))
+            self._read_exact(extra_len)
         if flag & FNAME:
             # Read and discard a null-terminated string containing the filename
             while True: