CVE-2019-3654: Client Proxy (MCP) - Authentication Bypass vulnerability

Severity: high (CVSS 8.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2019-11-22 · updated 2026-06-17
Weakness: CWE-287

Description

Authentication Bypass vulnerability in the Microsoft Windows client in McAfee Client Proxy (MCP) prior to 3.0.0 allows local user to bypass scanning of web traffic and gain access to blocked sites for a short period of time via generating an authorization key on the client which should only be generated by the network administrator.

Affected products

McAfee Client Proxy (MCP): before 3.0.0 — fixed in 3.0.0

How to fix

Upgrade to a fixed version: McAfee Client Proxy (MCP) 3.0.0. Check the vendor advisory for mitigations.

References

https://kc.mcafee.com/corporate/index?page=content&id=SB10305
https://kc.mcafee.com/corporate/index?page=content&id=SB10305

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