CVE-2021-31251

CRITICAL

Chiyu-tech Bf-430 Firmware - Authentication Bypass

Title source: rule

Description

An authentication bypass in telnet server in BF-430 and BF431 232/422 TCP/IP Converter, BF-450M and SEMAC from CHIYU Technology Inc allows obtaining a privileged connection with the target device by supplying a specially malformed request and an attacker may force the remote telnet server to believe that the user has already authenticated.

Exploits (1)

exploitdb WORKING POC

by sirpedrotavares · pythonremotehardware

https://www.exploit-db.com/exploits/49936

View Code ZIP pw:eip

References (3)

[Exploit, Third Party Advisory] https://gitbook.seguranca-informatica.pt/cve-and-exploits/cves/chiyu-iot-devices#cve-2021-31251

[Exploit, Third Party Advisory] https://seguranca-informatica.pt/dancing-in-the-iot-chiyu-devices-vulnerable-to-remote-attacks/#.YLqK1KhKguU

[Vendor Advisory] https://www.chiyu-tech.com/msg/message-Firmware-update-87.html

Scores

CVSS v3 9.8

EPSS 0.1084

EPSS Percentile 93.4%

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Details

CWE

CWE-287

Status published

Products (10)

chiyu-tech/bf-430_firmware

chiyu-tech/bf-431_firmware

chiyu-tech/bf-450m_firmware

chiyu-tech/semac_d1_firmware

chiyu-tech/semac_d2_firmware

chiyu-tech/semac_d2_n300_firmware

chiyu-tech/semac_d4_firmware

chiyu-tech/semac_s1_osdp_firmware

chiyu-tech/semac_s2_firmware

chiyu-tech/semac_s3v3_firmware

Published Jun 04, 2021

Tracked Since Feb 18, 2026