Huawei USG6300 V100R001C30SPC300 and USG6600 with software of V100R001C30SPC500,V100R001C30SPC600,V100R001C30SPC700,V100R001C30SPC800 have a weak algorithm vulnerability. Attackers may exploit the weak algorithm vulnerability to crack the cipher text and cause confidential information leaks on the transmission links.