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CVE-2021-31249

40
FAUCET Score

CVE-2021-31249 is a CRLF injection vulnerability affecting CHIYU Technology Inc.'s BF-430, BF-431, and BF-450M TCP/IP Converter devices due to insufficient validation of the 'redirect=' parameter in various CGI components. This medium-severity vulnerability (CVSS 6.5) allows unauthenticated attackers to achieve low impact on confidentiality and integrity with low attack complexity, potentially leading to HTTP response splitting or other injection attacks. While there is no evidence of active exploitation or public exploit code like Metasploit or ExploitDB entries, Nuclei templates exist for detection, and the vulnerability has received minimal community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:o:chiyu-tech:bf-430_firmware:-:*:*:*:*:*:*:*
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:o:chiyu-tech:bf-431_firmware:-:*:*:*:*:*:*:*
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:o:chiyu-tech:bf-450m_firmware:-:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

6.5MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
2.5
CvssVersion
3.1

Exploit Intelligence

EPSS Score
18.00%
Probability of exploitation in next 30 days
EPSS Percentile
96.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
Nuclei: CVE-2021-31249 · Jul 26, 2021
This CVE's current EPSS score of 0.1800 is in the 97th percentile among its peer group of 23,723 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

gitbook.seguranca-informatica.pt / cve-and-exploits/cves/chiyu-iot-devices
ExploitThird Party Advisory
seguranca-informatica.pt / dancing-in-the-iot-chiyu-devices-vulnerable-to-remote-attacks
ExploitThird Party Advisory
chiyu-tech.com / msg/message-Firmware-update-87.html
Vendor Advisory