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CVE-2026-20230

Cisco Unified Communications Manager Server-Side Request Forgery Vulnerability

Published: Jun 3, 2026Updated: Jul 22, 2026 Sources: CVE List NVD BDUCWE-918
8.6HIGH
NVD MITRE
EPSS Score
80.9%
Top 0.4%
CISA KEV
Active Exploitation
Since Jun 25, 2026
Exploits
0 Known
Remediation
Patch Available
Self-Check
OpenVAS

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.

In plain language

AI Act now

CVE-2026-20230 is a serious Cisco Unified Communications Manager problem that lets a hacker send special requests without logging in and—if the WebDialer service is turned on—could write files and gain full control of the server; most small businesses should treat this as urgent if they run these products.

Executive summary

CVE-2026-20230 is an unauthenticated, remote file-write and privilege-escalation risk in Cisco Unified Communications Manager (Unified CM) and Cisco Unified Communications Manager Session Management Edition (Unified CM SME), triggered via crafted HTTP requests that can lead to SSRF and (when WebDialer is enabled) root access. This issue is listed in CISA KEV and has been actively exploited in the wild.

If affected, business impact
Full server takeover (root access)Service disruptionInstallation of persistent malwareConfidential call/service data exposure

What to do now

  1. Check whether your Cisco Unified Communications Manager or Cisco Unified Communications Manager Session Management Edition has the WebDialer service enabled.
  2. If WebDialer is enabled (or you’re unsure), treat the system as exposed to this unauthenticated remote attack path.
  3. Contact your Cisco/IT vendor immediately and request the fixed update per Cisco’s advisory for CVE-2026-20230.
  4. Apply the vendor-recommended mitigations/patch as soon as possible, targeting the CISA due date (2026-06-28).
  5. If you cannot patch quickly, disable WebDialer and follow Cisco’s guidance for compensating controls, then validate the change in your configuration.
Some work to apply

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:CC:NI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:CScope
Changed
Impact
C:NConfidentiality
None
I:HIntegrity
High
A:NAvailability
None
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Weaknesses

CWE-918

Affected Products

Cisco Systems Inc.
commercial·USaka Cisco, cisco systems
Cisco Unified Communications Manager
Networking Infrastructure
Cisco Unified Communications Manager SME
Networking Infrastructure
unified communications manager
Networking Infrastructure
and 1 more affected products View all →

Exploitability

CISA Known Exploited Vulnerability
Added to KEV:Jun 25, 2026
Remediation 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.

0 exploit sources identified

Exploit details including PoC links, Metasploit modules, and scanner templates are available after registration.

View exploit details
Official Patch Available
Is your org exposed to CVE-2026-20230?We can run the check for you — a free external exposure review, no install. Check my exposure

Attack Graph

Products CVE Techniques Tactics

Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.

MITRE ATT&CK

2 techniques
Command and Control
Initial Access
View detailed technique mapping

References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cucm-ssrf-cXPnHcW
sec.cloudapps.cisco.com
https://undercodenews.com/cve-2026-20230-critical-cisco-unified-cm-ssrf-flaw-exposes-enterprises-to-root-level-takeover-via-public-exploit-code-video/
undercodenews.com
https://www.acn.gov.it/portale/w/cisco-cucm-disponibile-poc-per-lo-sfruttamento-di-vulnerabilita
acn.gov.it
and 3 more references View all →
News mentions
16
See all →

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