---
id: "CVE-2026-20230"
kind: "vulnerability"
aliases: ["CVE-2026-20230"]
title: "A vulnerability in Cisco Unified Communications Manager (Unified CM) and Cisco Unified Communications Manager\u2026"
severity: "critical"
cvss: 8.6
epss: null
exploited: true
status: "open"
category: "vendor"
products: [{"name": "cisco unified communications manager", "fixed": ["14su6"], "affected": ">= 14.0, < 14su6", "ecosystem": "vendor"}, {"name": "cisco unified communications manager", "fixed": [], "affected": ">= 15.0, <= 15su4a", "ecosystem": "vendor"}, {"name": "Cisco Unified Communications Manager", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["cisco", "exploited", "self-hosted", "unified-cm", "vendor", "voice"]
not_affected_if: ["no-unified-cm", "unaffected-version"]
published_at: "2026-06-03T18:16:20+00:00"
first_seen_at: "2026-10-23T19:11:51+00:00"
updated_at: "2026-10-24T00:09:50+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2026-20230", "first_seen_at": "2026-10-23T19:11:51+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-20230", "first_seen_at": "2026-10-23T23:44:51+00:00"}]
---

# A vulnerability in Cisco Unified Communications Manager (Unified CM) and Cisco Unified Communications Manager…

A server-side request forgery flaw in Cisco Unified Communications Manager and Unified CM Session Management Edition lets an unauthenticated remote attacker make the server write files to the underlying operating system. Attackers can use those written files later to escalate to root.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:cisco unified communications manager affected >= 14.0, < 14su6 fixed 14su6
- vendor:cisco unified communications manager affected >= 15.0, <= 15su4a fixed ?
- vendor:Cisco Unified Communications Manager affected ? fixed ?

## Fix

Apply the mitigations and fixed release from Cisco's advisory, as required by CISA KEV; the sources do not name a version. Follow CISA BOD 26-04 guidance and forensic triage requirements.

## Timeline

- 2026-10-23T19:11:51+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2026-20230
- 2026-10-23T23:44:51+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-20230

## From the sources

A vulnerability in Cisco Unified Communications Manager (Unified CM) and Cisco Unified Communications Manager Session Management Edition (Unified CM SME) could allow an unauthenticated, remote attacker to conduct server-side request forgery (SSRF) attacks through an affected device.

This vulnerability is due to improper input validation for specific HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to an affected device. A successful exploit could allow the attacker to write files to the underlying operating system that could be used later to elevate to root.
Note: Cisco has assigned this security advisory a Security Impact Rating (SIR) of Critical rather than High as the score indicates. The reason is that exploitation of this vulnerability could result in an attacker elevating privileges to root.
Note: To exploit this vulnerability, the WebDialer service must be enabled. WebDialer is disabled by default.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_