CVE-2020-3231: Cisco IOS Software for Catalyst 2960-L Series Switches and Catalyst CDB-8P Switches 802.1X Authentication Bypass Vulnerability

Severity: medium (CVSS 4.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-06-03 · updated 2026-06-17
Weakness: CWE-284

Description

A vulnerability in the 802.1X feature of Cisco Catalyst 2960-L Series Switches and Cisco Catalyst CDB-8P Switches could allow an unauthenticated, adjacent attacker to forward broadcast traffic before being authenticated on the port. The vulnerability exists because broadcast traffic that is received on the 802.1X-enabled port is mishandled. An attacker could exploit this vulnerability by sending broadcast traffic on the port before being authenticated. A successful exploit could allow the attacker to send and receive broadcast traffic on the 802.1X-enabled port before authentication.

Affected products

Cisco IOS: 15.2(5)e2, 15.2(5)ex, 15.2(5a)e, 15.2(5b)e, 15.2(5c)e, 15.2(6)e (+16)

References

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