CVE-2023-20156

Cisco Small Business Series Switches Buffer Overflow Vulnerabilities

8.6 High

Multiple vulnerabilities in the web-based user interface of certain Cisco Small Business Series Switches could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition or execute arbitrary code with root privileges on an affected device. These vulnerabilities are due to improper validation of requests that are sent to the web interface. For more information about these vulnerabilities, see the Details section of this advisory.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: High

Exploit likelihood

1.51%Up 1.5 points since May 18, 2023

What each source reports

CVE List Score used 8.6

Cisco Small Business Series Switches Buffer Overflow Vulnerabilities

Record: CVE-2023-20156
CVSS 3.1: 8.6 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Weakness: CWE-120
Updated: 2026-11-02

EUVDEUVD-2023-24335 8.6

Record: EUVD-2023-24335
CVSS 3.1: 8.6 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Updated: 2026-11-03

GitHub AdvisoriesGHSA-cvm9-664r-fv44 8.6

Multiple vulnerabilities in the web-based user interface of certain Cisco Small Business Series...

Record: GHSA-cvm9-664r-fv44
CVSS 3.0: 8.6 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Weakness: CWE-120
Updated: 2026-11-02

NVD 8.6

Record: CVE-2023-20156
CVSS 3.1: 8.6 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-120
Updated: 2026-11-02

Affected products

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History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD

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

In short

CVE-2023-20156 is a high vulnerability (CVSS 8.6) in Cisco 250 Series Smart Switches Firmware, published May 18, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.51%, the 74th percentile. No source names a fixed version.