CVE-2021-31642Public exploitNetwork attack vector

Authenticated device crash via oversized page parameter

Published Jun 1, 2021 · Updated Aug 3, 2024

Integer overflow in CHIYU BIOSENSE, Webpass, BF-630, BF-631, and SEMAC firmware allows remote authenticated users to crash devices. The if.cgi handler processes the page parameter without rejecting values wider than 32 bits, causing an integer overflow when a crafted access-log request is parsed. Access to the authenticated web portal is required; successful exploitation leaves the portal unavailable until the device is rebooted.

CVSS severity6.5
Medium
EPSS probability43.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer overflow in CHIYU BIOSENSE, Webpass, BF-630, BF-631, and SEMAC firmware allows remote authenticated users to crash devices. The if.cgi handler processes the page parameter without rejecting values wider than 32 bits, causing an integer overflow when a crafted access-log request is parsed. Access to the authenticated web portal is required; successful exploitation leaves the portal unavailable until the device is rebooted.

The record

CVE
CVE-2021-31642
Published
Jun 1, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-190, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 1, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
6.8NIST NVDAV:N/AC:L/Au:S/C:N/I:N/A:C

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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