How severe is CVE-2021-31641?

CVE-2021-31641 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-31641 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-31641?

CVE-2021-31641 primarily affects Chiyu-tech Bf-430 Firmware. In total, 15 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-31641?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-31641 published?

CVE-2021-31641 was published on 2021-06-01 and last updated on 2026-06-17.

CVE-2021-31641

CVE-2021-31641 is a medium-severity vulnerability in Chiyu-tech Bf-430 Firmware with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 4.3
EPSS exploit prediction: 5% (91st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Chiyu-tech Bf-430 Firmware
Published: 2021-06-01
Last modified: 2026-06-17

Description

An unauthenticated XSS vulnerability exists in several IoT devices from CHIYU Technology, including BF-630, BF-450M, BF-430, BF-431, BF631-W, BF830-W, Webpass, BF-MINI-W, and SEMAC due to a lack of sanitization when the HTTP 404 message is generated.

Frequently asked questions

What is CVE-2021-31641?: An unauthenticated XSS vulnerability exists in several IoT devices from CHIYU Technology, including BF-630, BF-450M, BF-430, BF-431, BF631-W, BF830-W, Webpass, BF-MINI-W, and SEMAC due to a lack of sanitization when the HTTP 404 message is generated.
How severe is CVE-2021-31641?: CVE-2021-31641 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-31641 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-31641?: CVE-2021-31641 primarily affects Chiyu-tech Bf-430 Firmware. In total, 15 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-31641?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-31641 published?: CVE-2021-31641 was published on 2021-06-01 and last updated on 2026-06-17.

References

Affected products (15)

cpe:2.3:o:chiyu-tech:bf-430_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:chiyu-tech:bf-431_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:chiyu-tech:bf-450m_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:chiyu-tech:semac_s2_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:chiyu-tech:semac_d1_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:chiyu-tech:semac_d2_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:chiyu-tech:semac_d4_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:chiyu-tech:semac_s3v3_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:chiyu-tech:semac_d2_n300_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:chiyu-tech:semac_s1_osdp_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:chiyu-tech:bf-630_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:chiyu-tech:bf-631w_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:chiyu-tech:bf-830w_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:chiyu-tech:webpass_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:chiyu-tech:bfminiw_firmware:-:*:*:*:*:*:*:*

More vulnerabilities in Chiyu-tech Bf-430 Firmware

CVE-2021-31251 — Critical (CVSS 9.8): An authentication bypass in telnet server in BF-430 and BF431 232/422 TCP/IP Converter, BF-450M and SEMAC from CHIYU…
CVE-2021-31249 — Medium (CVSS 6.5): A CRLF injection vulnerability was found on BF-430, BF-431, and BF-450M TCP/IP Converter devices from CHIYU Technology…
CVE-2021-31252 — Medium (CVSS 6.1): An open redirect vulnerability exists in BF-630, BF-450M, BF-430, BF-431, BF631-W, BF830-W, Webpass, and SEMAC devices…
CVE-2021-31250 — Medium (CVSS 5.4): Multiple storage XSS vulnerabilities were discovered on BF-430, BF-431 and BF-450M TCP/IP Converter devices from CHIYU…

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