CVE-2023-20259

What it is

A vulnerability in an API endpoint of multiple Cisco Unified Communications Products could allow an unauthenticated, remote attacker to cause high CPU utilization, which could impact access to the web-based management interface and cause delays with call processing. This API is not used for device management and is unlikely to be used in normal operations of the device. This vulnerability is due to improper API authentication and incomplete validation of the API request. An attacker could exploit this vulnerability by sending a crafted HTTP request to a specific API on the device. A successful exploit could allow the attacker to cause a denial of service (DoS) condition due to high CPU utilization, which could negatively impact user traffic and management access. When the attack stops, the device will recover without manual intervention.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

0.8% chance of exploitation in the next 30 days (EPSS).

Fix

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

Timeline

1. 2023-10-04 17:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 05:30 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.8% in the next 30 days (EPSS).
• Severity: 8.6 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2023-10-04 17:15 UTC

Last modified

2026-06-17 05:30 UTC

Exploit probability

0.8% · EPSS, next 30 days

Weakness

CWE-400 · Uncontrolled resource consumption

Record status

Modified

Affected

• Cisco Emergency Responder 14su3
• Cisco Prime Collaboration Deployment 14su3
• Cisco Unified Communications Manager 12.5\(1\)su7
• Cisco Unified Communications Manager 14su3
• Cisco Unified Communications Manager Im \& Presence Service 12.5\(1\)su7
• Cisco Unified Communications Manager Im \& Presence Service 14su3
• Cisco Unity Connection 14su3

Attack profile CVSS 3.1 · 8.6

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Changed

Confidentiality

None

Integrity

None

Availability

High

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-2023-20259.md and follow it. Check whether this project is affected by CVE-2023-20259. 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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