CRITICAL

CVE-2021-31251

CVSS v3

9.8

CRITICAL

EPSS Score

35.7 %

exploit probability, as of 2026-10-19

CISA KEV

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2021-31251 yet.

Full record on NVD

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.

Technical details

Published: 2021-06-04
Exploit-DB: EDB-49936

Frequently asked questions

What is CVE-2021-31251?

Is CVE-2021-31251 actively exploited?

Active exploitation of CVE-2021-31251 has not been confirmed. Its EPSS score was 35.7% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-31251?

CVE-2021-31251 has a CVSS v3 base score of 9.8 (CRITICAL severity).

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