CVE-2021-40127: Cisco SF200-24 Firmware

Medium severity, CVSS 5.3. EPSS: 1.3% chance of exploitation in the next 30 days.

A vulnerability in the web-based management interface of Cisco Small Business 200 Series Smart Switches, Cisco Small Business 300 Series Managed Switches, and Cisco Small Business 500 Series Stackable Managed Switches could allow an unauthenticated, remote attacker to render the web-based management interface unusable, resulting in a denial of service (DoS) condition. This vulnerability is due to improper validation of HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to an affected device. A successful exploit could allow the attacker to cause a permanent invalid redirect for requests sent to the web-based management interface of the device, resulting in a DoS condition.

Affected products

  • Cisco SF200-24 Firmware: affected versions not specified
  • Cisco SF200-24fp Firmware: affected versions not specified
  • Cisco SF200-24p Firmware: affected versions not specified
  • Cisco SF200-48 Firmware: affected versions not specified
  • Cisco SF200-48p Firmware: affected versions not specified
  • Cisco SF200E-24 Firmware: affected versions not specified
  • Cisco SF200E-24p Firmware: affected versions not specified
  • Cisco SF200E-48 Firmware: affected versions not specified
  • Cisco SF200E-48p Firmware: affected versions not specified
  • Cisco SF300-08 Firmware: version 1.4.11.02 only
  • Cisco SF300-24 Firmware: version 1.4.11.02 only
  • Cisco SF300-24mp Firmware: version 1.4.11.02 only
  • Cisco SF300-24p Firmware: version 1.4.11.02 only
  • Cisco SF300-24pp Firmware: version 1.4.11.02 only
  • Cisco SF300-48 Firmware: version 1.4.11.02 only
  • Cisco SF300-48p Firmware: version 1.4.11.02 only
  • Cisco SF300-48pp Firmware: version 1.4.11.02 only
  • Cisco SF302-08 Firmware: version 1.4.11.02 only
  • Cisco SF302-08mp Firmware: version 1.4.11.02 only
  • Cisco SF302-08mpp Firmware: version 1.4.11.02 only
  • Cisco SF302-08p Firmware: version 1.4.11.02 only
  • Cisco SF302-08pp Firmware: version 1.4.11.02 only
  • Cisco SF500-24 Firmware: affected versions not specified
  • Cisco SF500-24mp Firmware: affected versions not specified
  • Cisco SF500-24p Firmware: affected versions not specified
  • and 41 more

Published 2021-11-04. Last modified 2026-06-17.