An authentication bypass in telnet server in BF-430 and BF431 232/422 TCP/IP Converter…
Priority HIGH 68CWE-287Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-287.
Summary
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.
Why it matters now
EPSS 0.35714 98th percentileScored 2026-11-07
Public exploit Yes 2 exploit referencesTagged by NVD
Fix No fix listed No fixed version in the sources yet
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 20
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:chiyu-tech:bf-430_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | Chiyu-tech |
| cpe:2.3:h:chiyu-tech:bf-430:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Chiyu-tech |
| cpe:2.3:o:chiyu-tech:bf-431_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | Chiyu-tech |
| cpe:2.3:h:chiyu-tech:bf-431:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Chiyu-tech |
| cpe:2.3:o:chiyu-tech:bf-450m_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | Chiyu-tech |
| cpe:2.3:h:chiyu-tech:bf-450m:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Chiyu-tech |
| cpe:2.3:o:chiyu-tech:semac_s2_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | Chiyu-tech |
| cpe:2.3:h:chiyu-tech:semac_s2:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Chiyu-tech |
| cpe:2.3:o:chiyu-tech:semac_d1_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | Chiyu-tech |
| cpe:2.3:h:chiyu-tech:semac_d1:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Chiyu-tech |
- cpe:2.3:o:chiyu-tech:bf-430_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Chiyu-tech
- cpe:2.3:h:chiyu-tech:bf-430:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Chiyu-tech
- cpe:2.3:o:chiyu-tech:bf-431_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Chiyu-tech
- cpe:2.3:h:chiyu-tech:bf-431:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Chiyu-tech
- cpe:2.3:o:chiyu-tech:bf-450m_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Chiyu-tech
- cpe:2.3:h:chiyu-tech:bf-450m:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Chiyu-tech
- cpe:2.3:o:chiyu-tech:semac_s2_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Chiyu-tech
- cpe:2.3:h:chiyu-tech:semac_s2:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Chiyu-tech
- cpe:2.3:o:chiyu-tech:semac_d1_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Chiyu-tech
- cpe:2.3:h:chiyu-tech:semac_d1:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Chiyu-tech
Show 10 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:chiyu-tech:semac_d2_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | Chiyu-tech |
| cpe:2.3:h:chiyu-tech:semac_d2:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Chiyu-tech |
| cpe:2.3:o:chiyu-tech:semac_d4_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | Chiyu-tech |
| cpe:2.3:h:chiyu-tech:semac_d4:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Chiyu-tech |
| cpe:2.3:o:chiyu-tech:semac_s3v3_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | Chiyu-tech |
| cpe:2.3:h:chiyu-tech:semac_s3v3:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Chiyu-tech |
| cpe:2.3:o:chiyu-tech:semac_d2_n300_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | Chiyu-tech |
| cpe:2.3:h:chiyu-tech:semac_d2_n300:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Chiyu-tech |
| cpe:2.3:o:chiyu-tech:semac_s1_osdp_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | Chiyu-tech |
| cpe:2.3:h:chiyu-tech:semac_s1_osdp:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Chiyu-tech |
- cpe:2.3:o:chiyu-tech:semac_d2_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Chiyu-tech
- cpe:2.3:h:chiyu-tech:semac_d2:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Chiyu-tech
- cpe:2.3:o:chiyu-tech:semac_d4_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Chiyu-tech
- cpe:2.3:h:chiyu-tech:semac_d4:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Chiyu-tech
- cpe:2.3:o:chiyu-tech:semac_s3v3_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Chiyu-tech
- cpe:2.3:h:chiyu-tech:semac_s3v3:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Chiyu-tech
- cpe:2.3:o:chiyu-tech:semac_d2_n300_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Chiyu-tech
- cpe:2.3:h:chiyu-tech:semac_d2_n300:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Chiyu-tech
- cpe:2.3:o:chiyu-tech:semac_s1_osdp_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Chiyu-tech
- cpe:2.3:h:chiyu-tech:semac_s1_osdp:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Chiyu-tech
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2021-31251
- 2026-10-03 Alias added: GHSA-fr6h-7w99-6jxc
References
More Chiyu-tech Bf-430 Firmware vulnerabilities
- TI-2021-11449 Multiple storage XSS vulnerabilities were discovered on BF-430, BF-431 and BF-450M TCP/IP… CVSS 3.1MEDIUM 5.4
- TI-2021-11451 An open redirect vulnerability exists in BF-630, BF-450M, BF-430, BF-431, BF631-W… CVSS 3.1MEDIUM 6.1
- TI-2021-11448 A CRLF injection vulnerability was found on BF-430, BF-431, and BF-450M TCP/IP Converter… CVSS 3.1MEDIUM 6.5
- TI-2021-11724 An unauthenticated XSS vulnerability exists in several IoT devices from CHIYU Technology… CVSS 3.1MEDIUM 6.1
Sources
- CVE-2021-31251 · CVE Program
- CVE-2021-31251 · NVD
- FIRST EPSS
- GHSA-fr6h-7w99-6jxc · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences