diff --git a/contrib/epee/include/gzip_encoding.h b/contrib/epee/include/gzip_encoding.h
index 8b6721fa..dd89b25f 100644
--- a/contrib/epee/include/gzip_encoding.h
+++ b/contrib/epee/include/gzip_encoding.h
@@ -311,8 +311,8 @@ namespace net_utils
           result_packed_buff.resize(result_packed_buff.size()*2);
           continue;
         }        
-        if (result_packed_buff.size() != m_zstream.avail_out)
-          result_packed_buff.resize(result_packed_buff.size() - m_zstream.avail_out);
+        CHECK_AND_ASSERT_MES(result_packed_buff.size() >= m_zstream.avail_out, false, "result_packed_buff.size()=" << result_packed_buff.size() << " >= m_zstream.avail_out=" << m_zstream.avail_out);
+        result_packed_buff.resize(result_packed_buff.size() - m_zstream.avail_out);
         break;
       }