CVE-2026-20230

Published Jun 3, 2026

Last updated 20 days ago

Network

Server

Overview

AI description

Automated description summarized from trusted sources.

CVE-2026-20230 is an unauthenticated Server-Side Request Forgery (SSRF) vulnerability found in the WebDialer component of Cisco Unified Communications Manager (Unified CM) and Unified CM Session Management Edition. This flaw stems from improper input validation of specific HTTP requests, allowing a remote, unauthenticated attacker to send crafted requests. Successful exploitation of this vulnerability enables an attacker to write arbitrary files to the underlying operating system. These files can subsequently be used to escalate privileges to root on the affected system. While proof-of-concept exploit code is publicly available, Cisco has not observed active exploitation of this vulnerability. The affected WebDialer service is disabled by default, meaning only deployments where it has been explicitly enabled are susceptible.

Description: 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.
Source: psirt@cisco.com
NVD status: Analyzed
Products: unified_communications_manager

Risk scores

CVSS 3.1

Type: Secondary
Base score: 8.6
Impact score: 4
Exploitability score: 3.9
Vector string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
Severity: HIGH

Known exploits

Data from CISA

Vulnerability name: Cisco Unified Communications Manager Server-Side Request Forgery (SSRF) Vulnerability
Exploit added on: Jun 25, 2026
Exploit action due: Jun 28, 2026
Required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Weaknesses

psirt@cisco.com: CWE-918

Hype score: Not currently trending

Configurations

[
  {
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:cisco:unified_communications_manager:*:*:*:*:-:*:*:*",
            "matchCriteriaId": "9E708402-3D51-4165-8A97-2B3E68116553",
            "versionEndExcluding": "14su6",
            "versionStartIncluding": "14.0",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:cisco:unified_communications_manager:*:*:*:*:session_management:*:*:*",
            "matchCriteriaId": "321D5CC9-ECFC-42FD-AAB4-465E3BC399DA",
            "versionEndExcluding": "14su6",
            "versionStartIncluding": "14.0",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:cisco:unified_communications_manager:*:*:*:*:-:*:*:*",
            "matchCriteriaId": "EFBE275E-8043-4F8B-ABE8-48774CF11648",
            "versionEndIncluding": "15su4a",
            "versionStartIncluding": "15.0",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:cisco:unified_communications_manager:*:*:*:*:session_management:*:*:*",
            "matchCriteriaId": "06300542-9590-4FE0-8054-7BD15B2CB3BA",
            "versionEndIncluding": "15su4a",
            "versionStartIncluding": "15.0",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ]
  }
]

References

Sources include official advisories and independent security research.