How severe is CVE-2021-31642?

CVE-2021-31642 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-31642 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 44% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-31642?

CVE-2021-31642 primarily affects Chiyu-tech Semac S2 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-2021-31642?

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

When was CVE-2021-31642 published?

CVE-2021-31642 was published on 2021-06-01 and last updated on 2026-06-17.

CVE-2021-31642

CVE-2021-31642 is a medium-severity vulnerability in Chiyu-tech Semac S2 Firmware with a CVSS 3.x base score of 6.5. Its EPSS exploit-prediction score of 44% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-190.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 6.8
EPSS exploit prediction: 44% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-190
Affected product: Chiyu-tech Semac S2 Firmware
Published: 2021-06-01
Last modified: 2026-06-17

Description

A denial of service condition exists after an integer overflow in several IoT devices from CHIYU Technology, including BIOSENSE, Webpass, and BF-630, BF-631, and SEMAC. The vulnerability can be explored by sending an unexpected integer (> 32 bits) on the page parameter that will crash the web portal and making it unavailable until a reboot of the device.

Frequently asked questions

What is CVE-2021-31642?: A denial of service condition exists after an integer overflow in several IoT devices from CHIYU Technology, including BIOSENSE, Webpass, and BF-630, BF-631, and SEMAC. The vulnerability can be explored by sending an unexpected integer (> 32 bits) on the page parameter that will crash the web portal and making it unavailable until a reboot of the device.
How severe is CVE-2021-31642?: CVE-2021-31642 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-31642 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 44% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-31642?: CVE-2021-31642 primarily affects Chiyu-tech Semac S2 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-2021-31642?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-31642 published?: CVE-2021-31642 was published on 2021-06-01 and last updated on 2026-06-17.

References

Affected products (11)

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

More vulnerabilities in Chiyu-tech Semac S2 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-2021-31252 — 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-2021-31641 — Medium (CVSS 6.1): An unauthenticated XSS vulnerability exists in several IoT devices from CHIYU Technology, including BF-630, BF-450M,…
CVE-2021-31643 — Medium (CVSS 5.4): An XSS vulnerability exists in several IoT devices from CHIYU Technology, including SEMAC, Biosense, BF-630, BF-631,…

All CVEs affecting Chiyu-tech Semac S2 Firmware →

Other CWE-190 (Integer Overflow or Wraparound) vulnerabilities

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CVE-2025-64721 — Critical (CVSS 10.0): Sandboxie is a sandbox-based isolation software for 32-bit and 64-bit Windows NT-based operating systems. In versions…
CVE-2015-5108 — Critical (CVSS 10.0): Integer overflow in Adobe Reader and Acrobat 10.x before 10.1.15 and 11.x before 11.0.12, Acrobat and Acrobat Reader DC…
CVE-2015-5097 — Critical (CVSS 10.0): Integer overflow in Adobe Reader and Acrobat 10.x before 10.1.15 and 11.x before 11.0.12, Acrobat and Acrobat Reader DC…
CVE-2013-2555 — Critical (CVSS 10.0): Integer overflow in Adobe Flash Player before 10.3.183.75 and 11.x before 11.7.700.169 on Windows and Mac OS X, before…

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