CVE-2026-20230: Cisco Unified Communications Manager

What is CVE-2026-20230?

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.

CVSS8.6 NVD 3.1

SeverityHIGH

Exploitation In the wild In CISA KEV

EPSS88% · P100

Triage statusActive Exploit

ActionPatch immediately

CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N

CWECWE-918

NVD published2026-06-03

NVD last modified2026-10-07

Timeline

2026-06-03Published to the U.S. National Vulnerability Database (NVD)
2026-06-05First covered in a defend.network daily briefing
2026-06-25Added to the CISA Known Exploited Vulnerabilities (KEV) catalog
2026-06-28CISA federal remediation deadline (BOD 22-01)
2026-10-07NVD record last updated

CISA Known Exploited Vulnerability

Cisco Unified Communications Manager Server-Side Request Forgery (SSRF) Vulnerability

Added to KEV2026-06-25

Federal patch deadline2026-06-28

Known ransomware useUnknown

Affected product

Cisco Unified Communications Manager

Remediation Steps

Apply the vendor security update for Cisco Unified Communications Manager Server as a priority.
Restrict network exposure of the affected service to trusted sources until patched.
Review logs and detections for indicators of exploitation.
Confirm fixed versions against the official vendor advisory before deploying.

References

Referenced in our briefings & reports

Vulnerability Priority Report – Week 3 of July 2026 (July 20 – 26)
Vulnerability Priority Report – Week 2 of July 2026 (July 13 – 19)
Vulnerability Priority Report – Week 1 of July 2026 (July 6 – 12)
Vulnerability Priority Report – Week 5 of June 2026 (June 29 – July 5)
Vulnerability Priority Report – Week 4 of June 2026 (June 22 – 28)
Vulnerability Priority Report – Week 1 of June 2026 (June 1 – 7)
FortiBleed harvests 110M credentials; Cisco SSRF actively exploited; GitHub patches CI/CD attacks (2026-06-24)
Cisco Unified CM RCE, Claude GitHub Action Hijack, AI Agent Exploits (2026-06-05)

Browse all tracked CVEs in the defend.network CVE database →

🤖 This CVE page is generated by defend.network from NVD, CISA KEV, EPSS, and our verified daily briefings. Severity and exploitation data come from official sources; always verify remediation steps against the official vendor advisory before acting in production.