CVE-2024-20534: Cisco Desk Phone 9841 With Multiplatform Firmware

Medium severity, CVSS 4.8. EPSS: 0.3% chance of exploitation in the next 30 days.

A vulnerability in the web UI of Cisco Desk Phone 9800 Series, Cisco IP Phone 6800, 7800, and 8800 Series, and Cisco Video Phone 8875 with Cisco Multiplatform Firmware could allow an authenticated, remote attacker to conduct stored cross-site scripting (XSS) attacks against users. This vulnerability exists because the web UI of an affected device does not properly validate user-supplied input. An attacker could exploit this vulnerability by injecting malicious code into specific pages of the interface. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information. Note: To exploit this vulnerability, Web Access must be enabled on the phone and the attacker must have Admin credentials on the device. Web Access is disabled by default.

Affected products

  • Cisco Desk Phone 9841 With Multiplatform Firmware: version 3.1(1) only
  • Cisco Desk Phone 9851 With Multiplatform Firmware: version 3.1(1) only
  • Cisco Desk Phone 9861 With Multiplatform Firmware: version 3.1(1) only
  • Cisco Desk Phone 9871 With Multiplatform Firmware: version 3.1(1) only
  • Cisco IP Phone 6821 With Multiplatform Firmware: version 12.0(5) only
  • Cisco IP Phone 6841 With Multiplatform Firmware: version 12.0(5) only
  • Cisco IP Phone 6851 With Multiplatform Firmware: version 12.0(5) only
  • Cisco IP Phone 6861 With Multiplatform Firmware: version 12.0(5) only
  • Cisco IP Phone 6871 With Multiplatform Firmware: version 12.0(5) only
  • Cisco IP Phone 7811 With Multiplatform Firmware: version 12.0(5) only
  • Cisco IP Phone 7821 With Multiplatform Firmware: version 12.0(5) only
  • Cisco IP Phone 7832 With Multiplatform Firmware: version 12.0(5) only
  • Cisco IP Phone 7841 With Multiplatform Firmware: version 12.0(5) only
  • Cisco IP Phone 7861 With Multiplatform Firmware: version 12.0(5) only
  • Cisco IP Phone 8811 With Multiplatform Firmware: version 12.0(5) only
  • Cisco IP Phone 8831 With Multiplatform Firmware: affected versions not specified
  • Cisco IP Phone 8832 With Multiplatform Firmware: version 12.0(5) only
  • Cisco IP Phone 8841 With Multiplatform Firmware: version 12.0(5) only
  • Cisco IP Phone 8845 With Multiplatform Firmware: version 12.0(5) only
  • Cisco IP Phone 8851 With Multiplatform Firmware: version 12.0(5) only
  • Cisco IP Phone 8861 With Multiplatform Firmware: version 12.0(5) only
  • Cisco IP Phone 8865 With Multiplatform Firmware: version 12.0(5) only
  • Cisco Video Phone 8875 With Multiplatform Firmware: before 2.3\(1\) (fixed in 2.3\(1\)); version 2.3(1) only

Published 2024-11-06. Last modified 2026-06-17.