CVE-2020-3231

What it is

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.

At a glance

Exploitability

Can be exploited from the same network segment without logging in. Limited direct impact.

Exploit odds

0.5% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2020-06-03 18:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 03:17 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.5% in the next 30 days (EPSS).
• Severity: 4.7 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2020-06-03 18:15 UTC

Last modified

2026-06-17 03:17 UTC

Exploit probability

0.5% · EPSS, next 30 days

Weakness

CWE-284 · Improper access control

Record status

Modified

Affected

• Cisco iOS 15.2\(5\)e2
• Cisco iOS 15.2\(5\)ex
• Cisco iOS 15.2\(5a\)e
• Cisco iOS 15.2\(5b\)e
• Cisco iOS 15.2\(5c\)e
• Cisco iOS 15.2\(6\)e
• Cisco iOS 15.2\(6\)e0c
• Cisco iOS 15.2\(6\)e1

Attack profile CVSS 3.1 · 4.7

Attack vector

Adjacent network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Changed

Confidentiality

Low

Integrity

None

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2020-3231.md and follow it. Check whether this project is affected by CVE-2020-3231. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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