CVE-2020-3400: Cisco IOS XE Software Web UI Authorization Bypass Vulnerability

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-09-24 · updated 2026-06-17
Weakness: CWE-862

Description

A vulnerability in the web UI feature of Cisco IOS XE Software could allow an authenticated, remote attacker to utilize parts of the web UI for which they are not authorized.The vulnerability is due to insufficient authorization of web UI access requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to the web UI. A successful exploit could allow the attacker to utilize parts of the web UI for which they are not authorized. This could allow a Read-Only user to perform actions of an Admin user.

Affected products

Cisco IOS XE: 16.2.2, 16.3.1, 16.3.1a, 16.3.2, 16.3.3, 16.3.4 (+9)

References

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