What is CVE-2020-8839?

CVE-2020-8839 is a medium-severity vulnerability in Chiyu-T Bf-430, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2020-02-12.

How severe is CVE-2020-8839?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Is CVE-2020-8839 known to be exploited?

3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

XSS in Chiyu-T Bf-430

CVE-2020-8839

Stored XSS was discovered on CHIYU BF-430 232/485 TCP/IP Converter devices before 1.16.00, as demonstrated by the /if.cgi TF_submask field.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2020-02-12 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.021 (80.7th percentile), scored 2026-10-02.

Low probability of exploitation in the next 30 days, but still tracked. 81st percentile — 80.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.021 · newest: 0.021 · change: 0.000

Affected products

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

Public proof-of-concept exploits

References

drive.google.com/open (Exploit, Third Party Advisory)
packetstormsecurity.com/files/156289/CHIYU-BF430-TCP-IP-Converter-Cross-Site-Sc… (Exploit, VDB Entry, Third Party Advisory)

Frequently asked questions

What is CVE-2020-8839?: CVE-2020-8839 is a medium-severity vulnerability in Chiyu-T Bf-430, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2020-02-12.
How severe is CVE-2020-8839?: Medium severity. CVSS v3 base score is 6.1 out of 10.
Is CVE-2020-8839 known to be exploited?: 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.