CVE-2020-8839: Stored XSS was discovered on CHIYU BF-430 232/485 TCP/IP Converter devices before 1.16.00, as demonstrated by

Q: How do I fix CVE-2020-8839?

bf-430 firmware: upgrade to 1.16.00. Exact commands for each OS are on this page.

Q: Is CVE-2020-8839 being exploited?

CVE-2020-8839 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2020-8839 affect?

CVE-2020-8839 affects bf-430 firmware. Severity is medium (CVSS 6.1). 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.

Q: How urgent is CVE-2020-8839?

Priority 47/100. Public exploit reference

This month

MEDIUM 6.1UPGRADE

CVE-2020-8839 is a medium-severity flaw (CVSS 6.1) affecting bf-430 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	2.1% (top 19%)
CISA exploited list	No
Weakness	CWE-79
Published	2020-02-12
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: chiyu-t

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-02-12 15:15 UTCPublished CVE record published
2026-06-17 03:27 UTCUpdated Record last modified

chiyu-t bf-430 firmware UPGRADE

Affected: < 1.16.00

Fixed in: 1.16.00

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: CHIYU BF430 TCP IP Converter - Stored Cross-Site Scripting

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-8839?

bf-430 firmware: upgrade to 1.16.00. Exact commands for each OS are on this page.

Is CVE-2020-8839 being exploited?

CVE-2020-8839 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-8839 affect?

CVE-2020-8839 affects bf-430 firmware. Severity is medium (CVSS 6.1). 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.

How urgent is CVE-2020-8839?

Priority 47/100. Public exploit reference

Related CVEs

CVE-2021-31641 MEDIUM 6.1 MITIGATE MITIGATE An unauthenticated XSS vulnerability exists in several IoT devices from CHIYU Technology, including BF-630, BF
CVE-2021-31252 MEDIUM 6.1 MITIGATE MITIGATE An open redirect vulnerability exists in BF-630, BF-450M, BF-430, BF-431, BF631-W, BF830-W, Webpass, and SEMAC
CVE-2021-31251 CRITICAL 9.8 MITIGATE MITIGATE An authentication bypass in telnet server in BF-430 and BF431 232/422 TCP/IP Converter, BF-450M and SEMAC from
CVE-2021-31250 MEDIUM 5.4 MITIGATE MITIGATE Multiple storage XSS vulnerabilities were discovered on BF-430, BF-431 and BF-450M TCP/IP Converter devices fr
CVE-2021-31249 MEDIUM 6.5 MITIGATE MITIGATE A CRLF injection vulnerability was found on BF-430, BF-431, and BF-450M TCP/IP Converter devices from CHIYU Te

References

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