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CVE-2020-3231

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

4.7 Medium

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.

Attack profile

How easy it is to exploit

Attack vector
Adjacent network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
Low
Integrity
None
Availability
None

Exploit likelihood

0.45%Unchanged since Apr 14, 2021
90%50%10%1%

What each source reports

CVE List Score used 4.7

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

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.

Record
CVE-2020-3231
CVSS 3.0
4.7 MediumCVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
Weakness
CWE-284
Updated
2026-11-02
EUVDEUVD-2020-24502 4.7

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.

Record
EUVD-2020-24502
CVSS 3.0
4.7 MediumCVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
Updated
2026-11-03
GitHub AdvisoriesGHSA-q4w2-p3xv-w8vf 4.7

A vulnerability in the 802.1X feature of Cisco Catalyst 2960-L Series Switches and Cisco Catalyst...

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.

Record
GHSA-q4w2-p3xv-w8vf
CVSS 3.1
4.7 MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
Weakness
CWE-284, CWE-863
Updated
2026-11-02
NVD 4.7

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.

Record
CVE-2020-3231
CVSS 3.1
4.7 MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
CVSS 3.0
4.7 MediumCVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
CVSS 2.0
2.9 LowAV:A/AC:M/Au:N/C:P/I:N/A:N
Weakness
CWE-284, CWE-863
Updated
2026-11-02

Affected products

History

History
RecordedChangedSources
aliases, publishedEUVD
first indexedCVE List, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2020-3231 is a medium vulnerability (CVSS 4.7) in Cisco Ios, published June 3, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.45%, the 39th percentile. No source names a fixed version.

References

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