Design/Logic Flaw

The executable httpd on the TP-Link WR841N V8 router before TL-WR841N(UN)_V8_170210 contained a design flaw in the use of DES for block encryption. This resulted in incorrect access control, which allowed attackers to gain read-write access to system settings through the protected router configuration service tddp via the LAN and Ath0 (Wi-Fi) interfaces.