CVE intelligence and bounded remediation

CVE-2024-20534 — Cisco Desk Phone 9841 With Multiplatform Firmware security vulnerability

Medium CVSS 4.8

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.

Severity
Medium
CVSS
4.8 (3.1)
Published
2024-11-06
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-79

Affected products

  • cisco / desk_phone_9841_with_multiplatform_firmware / 3.1(1)
  • cisco / desk_phone_9851_with_multiplatform_firmware / 3.1(1)
  • cisco / desk_phone_9861_with_multiplatform_firmware / 3.1(1)
  • cisco / desk_phone_9871_with_multiplatform_firmware / 3.1(1)
  • cisco / ip_phone_6821_with_multiplatform_firmware / 12.0(5)
  • cisco / ip_phone_6841_with_multiplatform_firmware / 12.0(5)

Showing 6 representative product identities from 29 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Cross-site scripting and unsafe browser output

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

Check exposure

  • Trace reflected, stored, and DOM-derived untrusted values into HTML, attributes, URLs, styles, scripts, and client-side template sinks.
  • Identify affected origins, authenticated user roles, sensitive browser capabilities, and where content is shared across tenants.
  • Review framework escaping, rich-text sanitization, legacy templates, and client-side rendering paths.

Remediate safely

  • Use context-aware framework output encoding and safe DOM APIs; keep untrusted data out of executable contexts.
  • Sanitize intentionally supported markup with a maintained allowlist policy and validate URLs and attributes separately.
  • Update affected rendering components and add tests for every output context using inert sentinel markup.

Authoritative sources

Complete CVE record and remediation plan

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