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Known exploited vulnerability

CVE-2026-20230

highCVSS 3.1 8.6In CISA KEVEPSS 89%Published · Cisco

The short answer

CVE-2026-20230 affects Cisco Cisco Unified Communications Manager and is rated high (CVSS 8.6). CISA added it to the Known Exploited Vulnerabilities catalog on 2026-06-25: attackers are using it, so patch it first.

What it is

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.

Weakness: CWE-918.

Severity

8.6 high

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

Exploited (CISA KEV)

Yes, since Jun 25, 2026

Federal due date Jun 28, 2026

EPSS, next 30 days

89%

Higher than 100% of scored CVEs

How it can be exploited

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality impact
None
Integrity impact
High
Availability impact
None

What CISA says to do

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…

Affected products

Cisco Unified Communications Manager. NVD's record lists the exact affected versions.

References

Questions

Is CVE-2026-20230 being exploited?

Yes. CISA added CVE-2026-20230 to its Known Exploited Vulnerabilities catalog on 2026-06-25, with a federal remediation due date of 2026-06-28.

How do I fix CVE-2026-20230?

CISA's 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…

From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.

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