What it is
CVE-2021-31250 is a vulnerability affecting CHIYU Technology Inc BF-430 and 2 other products. Multiple storage XSS vulnerabilities were discovered on BF-430, BF-431 and BF-450M TCP/IP Converter devices from CHIYU...
Vulnerability report
Exploited in the wild
High confidence
Not in CISA KEV
CVE-2021-31250
BF-430 Cross-Site Scripting
CHIYU Technology Inc / BF-430
- Severity
- CVSS 5.4 · Medium
- Confidence
- High
- Exploit status
- Exploited in the wild
- EPSS
- 79.6%
- First observed
- —
- Last observed
- —
Decision summary
What security teams need to know first
Direct answers before the deeper technical record.
Is it exploited?
Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is high.
Who is affected?
CHIYU Technology Inc / BF-430.
What should we do?
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
Overview
BF-430 Cross-Site Scripting
Multiple storage XSS vulnerabilities were discovered on BF-430, BF-431 and BF-450M TCP/IP Converter devices from CHIYU Technology Inc due to a lack of sanitization of the input on the components man.cgi, if.cgi, dhcpc.cgi, ppp.cgi.
- Published
- 04 Jun 2021
- Exploitation Reported
- 16 Feb 2026
- Attack vector
- Remote
- Complexity
- Low
- Privileges
- Low
- User interaction
- Required
Tags
nuclei_scanner
CVE References
- CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2021-31250
- seguranca-informatica.pt/dancing-in-the-iot-chiyu-devices-vulnerable-... seguranca-informatica.pt · CVE Record https://seguranca-informatica.pt/dancing-in-the-iot-chiyu-devices-vul...
- gitbook.seguranca-informatica.pt/cve-and-exploits/cves/chiyu-iot-devices gitbook.seguranca-informatica.pt · CVE Record https://gitbook.seguranca-informatica.pt/cve-and-exploits/cves/chiyu-...
- chiyu-tech.com/msg/message-Firmware-update-87.htm chiyu-tech.com · CVE Record https://www.chiyu-tech.com/msg/message-Firmware-update-87.htm
Exploitation evidence
Why KEV Intelligence marks this CVE as exploited
Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.
Exploited in the wild
The Shadowserver
Independent exploitation attestation added to the KEV Intelligence record.
Proof of concept available
Nuclei Templates
Public scanner or PoC coverage increases practical exploitability.
Known exploited vulnerability sources
Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| The Shadowserver First | 2026-02-16 00:00 UTC |
Detection
Operational artifacts and observed signals
Make the evidence actionable in scanner, SOC, and edge-control workflows.
Observed signals
- Request targets
- 0
- User-Agents
- 0
Raw values available in Pro and Enterprise.
Scanner coverage
Nuclei template detected 25 Apr 2025.
View Nuclei template (opens in new tab)Virtual patch status
No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.
Learn about virtual patches →Scanner Artifacts
Scanner and exploit-framework references linked to this CVE.
| Scanner | Reference | Detected |
|---|---|---|
| Nuclei | https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-31250.yaml | 25 Apr 2025 |
Risk and context
Severity, weaknesses, and research context
CVSS v3.1
5.4
Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
EPSS
79.6%
All CVSS Scores
CVSS v3.1
5.4
Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CVSS v2.0
3.5
Low
AV:N/AC:M/Au:S/C:N/I:P/A:N
Potential Proof of Concepts
These PoCs are unverified and could contain malware. Use at your own risk.
CHIYU TCP/IP Converter - Cross-Site Scripting
nuclei · Created Unknown
Timeline
From disclosure to observed exploitation
-
Public PoC available
Public proof-of-concept code published
-
Added to KEV Intelligence KEV Feed
High-confidence, third-party attested exploitation
-
Nuclei template available
Scanner coverage available
-
CVE published
Vulnerability disclosed publicly
-
CVE ID reserved
Identifier reserved by the CNA
Pro API
Automate this intelligence
Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
- Evidence confidence and provenance
- First-party sensor telemetry
- PoC and scanner references
- Affected versions and enrichment
- Automation-ready JSON delivery
GET /api/v2/pro/kevs/CVE-2021-31250
Free JSON includes basic KEV fields{
"cve_id": "CVE-2021-31250",
"confidence": "High",
"cvss_score": 5.4,
"cvss_estimated": false,
"epss_score": 0.79605,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "attempts": 0, "sensors": 0 }
}Early warning alerts
Get alerts on high-impact exploitation
Receive curator-selected alerts when exploitation activity warrants attention. Each alert includes the evidence and context needed to decide what requires attention now.