How severe is CVE-2021-31643?

CVE-2021-31643 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-31643 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 88% (100th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-31643?

CVE-2021-31643 primarily affects Chiyu-tech Bf-631 Firmware. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-31643?

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

When was CVE-2021-31643 published?

CVE-2021-31643 was published on 2021-06-01 and last updated on 2026-06-17.

CVE-2021-31643

CVE-2021-31643 is a medium-severity vulnerability in Chiyu-tech Bf-631 Firmware with a CVSS 3.x base score of 5.4. Its EPSS exploit-prediction score of 88% places it in the 100th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v2: 3.5
EPSS exploit prediction: 88% (100th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Chiyu-tech Bf-631 Firmware
Published: 2021-06-01
Last modified: 2026-06-17

Description

An XSS vulnerability exists in several IoT devices from CHIYU Technology, including SEMAC, Biosense, BF-630, BF-631, and Webpass due to a lack of sanitization on the component if.cgi - username parameter.

Frequently asked questions

What is CVE-2021-31643?: An XSS vulnerability exists in several IoT devices from CHIYU Technology, including SEMAC, Biosense, BF-630, BF-631, and Webpass due to a lack of sanitization on the component if.cgi - username parameter.
How severe is CVE-2021-31643?: CVE-2021-31643 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-31643 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 88% (100th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-31643?: CVE-2021-31643 primarily affects Chiyu-tech Bf-631 Firmware. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-31643?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-31643 published?: CVE-2021-31643 was published on 2021-06-01 and last updated on 2026-06-17.

References

Affected products (11)

cpe:2.3:o:chiyu-tech:bf-631_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:chiyu-tech:bf-630_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:webpass_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:chiyu-tech:biosense_firmware:-:*:*:*:*:*:*:*

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