CVE intelligence and bounded remediation

CVE-2021-31642 — Chiyu-Tech Semac S2 Firmware security vulnerability

Medium CVSS 6.8

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.

Severity
Medium
CVSS
6.8 (2.0)
Published
2021-06-01
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-190

Affected products

  • chiyu-tech / semac_s2_firmware
  • chiyu-tech / semac_d1_firmware
  • chiyu-tech / semac_d2_firmware
  • chiyu-tech / semac_d4_firmware
  • chiyu-tech / semac_s3v3_firmware
  • chiyu-tech / semac_d2_n300_firmware

Showing 6 representative product identities from 11 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Buffer bounds, memory safety, and memory corruption

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Identify affected native-code versions, build flags, architectures, parsers, codecs, drivers, and input paths in all shipped artifacts.
  • Determine whether untrusted data reaches the affected routine and the process privilege, sandbox, and network exposure.
  • Confirm statically linked, vendored, firmware, and platform-provided copies, not only package-manager records.

Remediate safely

  • Apply the maintained upstream correction or replace the affected component, then rebuild every dependent artifact from clean inputs.
  • Adopt bounds-checked interfaces, validated sizes and integer conversions, clear ownership, and memory-safe components where practical.
  • Enable supported compiler and runtime hardening and add sanitized tests and fuzz regression seeds derived from non-weaponized fixtures.

Authoritative sources

Complete CVE record and remediation plan

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