CVE intelligence and bounded remediation

CVE-2024-20378 — Cisco Ip Phone 6821 With Multiplatform Firmware security vulnerability

High CVSS 7.5

A vulnerability in the web-based management interface of Cisco IP Phone firmware could allow an unauthenticated, remote attacker to retrieve sensitive information from an affected device. This vulnerability is due to a lack of authentication for specific endpoints of the web-based management interface on an affected device. An attacker could exploit this vulnerability by connecting to the affected device. A successful exploit could allow the attacker to gain unauthorized access to the device, enabling the recording of user credentials and traffic to and from the affected device, including VoIP calls that could be replayed.

Severity
High
CVSS
7.5 (3.1)
Published
2024-05-01
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-305

Affected products

  • cisco / ip_phone_6821_with_multiplatform_firmware
  • cisco / ip_phone_6821_with_multiplatform_firmware / 12.0.4
  • cisco / ip_phone_6841_with_multiplatform_firmware
  • cisco / ip_phone_6841_with_multiplatform_firmware / 12.0.4
  • cisco / ip_phone_6851_with_multiplatform_firmware
  • cisco / ip_phone_6851_with_multiplatform_firmware / 12.0.4

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

Matched remediation archetype

Authentication bypass and missing authentication

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Check exposure

  • Map every affected endpoint and protocol path, including alternate ports, legacy routes, recovery flows, service accounts, and machine-to-machine access.
  • Confirm which deployments enable the affected authentication mode and whether the interface is reachable from untrusted networks.
  • Review session, token, credential, and proxy trust configuration without attempting account takeover.

Remediate safely

  • Apply the supported fix and centralize fail-closed authentication before protected request handling.
  • Remove default or embedded credentials, rotate affected secrets and sessions, and bind authentication decisions to the intended audience and channel.
  • Add negative tests for alternate routes, malformed or absent credentials, recovery flows, and proxy-derived identity.

Authoritative sources

Complete CVE record and remediation plan

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