Exploited

CVE-2026-20230

Cisco Unified Communications Manager · Collaboration, telephony and video conferencing

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

At a glance

Exploited. Added to CISA’s catalog of exploited vulnerabilities on June 25, 2026.

Affected product: Cisco Unified Communications Manager (category Collaboration, telephony and video conferencing, indicative classification). Name in CISA’s catalog: Cisco Unified Communications Manager.

What should I do?

Apply the patches or mitigations from Cisco; if none are available, stop using the product. Start with internet-facing devices.

Deadline set by CISA for US federal agencies: 3 days (due June 28, 2026). It only binds those agencies, but it is a useful measure of urgency.

Cisco security advisories page (general page, not the advisory for this vulnerability)
The vendor’s specific advisory is listed in the NVD references: CVE-2026-20230 on the NVD website.

Original text of the required action (CISA)

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.

Timeline

June 3, 2026 Vulnerability published Publication date (NVD)
June 25, 2026 Exploitation confirmed Added to CISA’s KEV catalog
June 28, 2026 CISA deadline Remediation deadline set for US federal agencies

The facts, with their sources

Exploitation confirmed: Yes, on June 25, 2026 Date added to the catalog of exploited vulnerabilities. Exploitation itself may have started earlier. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
Ransomware: No known use to date That does not guarantee it is not being used: the information is not public. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
Hunt for compromise: Not requested by CISA Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
CISA required action: Apply the patches or mitigations from Cisco; if none are available, stop using the product. Start with internet-facing devices. Rewritten by this site from CISA’s original text. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
CISA deadline: June 28, 2026, 3 days Set for US federal agencies: a measure of urgency, not an obligation elsewhere. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
Vulnerability published: June 3, 2026 Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC
Product according to CISA: Cisco Unified Communications Manager Filed by this site under “Collaboration, telephony and video conferencing” (indicative classification). Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N Technical detail of the score: attack vector, complexity, impact. Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC

Severity and activity

8.6 / 10 CVSS severity: high

Score from the vendor or CISA, relayed by the NVD. Collected Sep 29, 2026.

— Probability of exploitation in the next 30 days (EPSS)

FIRST’s EPSS model. Since exploitation is already confirmed, this figure is mostly useful to compare activity. Collected Sep 29, 2026.

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.

Cisco Unified Communications Manager (Unified CM) and Cisco Unified Communications Manager Session Management Edition (Unified CM SME) contain a server-side request forgery (SSRF) Vulnerability that could allow an unauthenticated, remote attacker to write files to the underlying operating system that could be used later to elevate to root.

Summary from CISA (KEV catalog).

CERT-FR advisories

No advisory among the latest CERT-FR publications this site follows. That does not mean there are none.

Information reused under the Open Licence 2.0 (Etalab); the date of last update is shown for each advisory. This site is neither affiliated with nor endorsed by ANSSI.

Sources for this page

CISA KEV catalog: exploitation, date added, required action, deadline, ransomware.
NVD (NIST): CVSS severity, publication date, description, vendor references.
EPSS (FIRST): probability of exploitation.
CERT-FR: advisories and alerts (in French).
Brand and category: indicative classification by this site (method).