CVE-2021-31249

Exp

A CRLF injection vulnerability was found on BF-430, BF-431, and BF-450M TCP/IP Converter devices from CHIYU Technology Inc due to a lack of validation on the parameter redirect= available on multiple CGI components.

Published: 2021-06-04 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-31249 is rated High Exploit Risk (69.9/100): CVSS Medium severity, with high exploitation likelihood (EPSS 18.00%, 97th percentile). 2 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-31249

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-31249

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 90.44% 18.00% -72.44%
2 2026-05-21 89.99% 90.44% +0.45%
3 2026-02-28 — 89.99% —

Full EPSS history (26 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-31249

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 2.5 [email protected]
6.4 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 4.9 [email protected]

Weakness enumeration for CVE-2021-31249

Affected software / configurations for CVE-2021-31249

Vendor Product Version Raw CPE
chiyu-tech bf-430_firmware — cpe:2.3:o:chiyu-tech:bf-430_firmware:-:*:*:*:*:*:*:*
chiyu-tech bf-431_firmware — cpe:2.3:o:chiyu-tech:bf-431_firmware:-:*:*:*:*:*:*:*
chiyu-tech bf-450m_firmware — cpe:2.3:o:chiyu-tech:bf-450m_firmware:-:*:*:*:*:*:*:*

References for CVE-2021-31249

cvelogic Threat Intelligence