A vulnerability in Cisco Unified Communications Manager (Unified CM), Cisco Unified Communications Manager Session Management Edition (Unified CM SME), Cisco Unified Communications Manager IM &amp; Presence Service (Unified CM IM&amp;P), Cisco Unity Connection, and Cisco Webex Calling Dedicated Instance could allow an unauthenticated, remote attacker&nbsp;to execute arbitrary commands on the underlying operating system of an affected device.&nbsp; This vulnerability is due to improper validation of user-supplied input in HTTP requests. An attacker could exploit this vulnerability by sending a sequence of crafted HTTP requests to the web-based management interface of an affected device. A successful exploit could allow the attacker to obtain user-level access to the underlying operating system and then elevate privileges 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.

Cisco reports that attempted exploitation has been observed and this RCE has been rated as critical. Immediate patching is recommended

Cisco is aware of attempted exploitation of this zero-day vulnerability. Patching as soon as possible is strongly advised.

According to its self-reported version, Cisco Unified Communications Manager IM & Presence is affected by a remote code execution vulnerability:

  - A vulnerability in Cisco Unified Communications Manager (Unified CM), Cisco Unified Communications Manager Session     Management Edition (Unified CM SME), Cisco Unified Communications Manager IM & Presence Service (Unified CM IM&P),     Cisco Unity Connection, and Cisco Webex Calling Dedicated Instance could allow an unauthenticated, remote attacker     to execute arbitrary commands on the underlying operating system of an affected device. This vulnerability is due to     improper validation of user-supplied input in HTTP requests. An attacker could exploit this vulnerability by sending     a sequence of crafted HTTP requests to the web-based management interface of an affected device. A successful     exploit could allow the attacker to obtain user-level access to the underlying operating system and then elevate     privileges to root. (CVE-2026-20045)

Please see the included Cisco BID and Cisco Security Advisory for more information.

According to its self-reported version, the remote Cisco Unified Communications Manager is affected by a remot code execution vulnerability:

  - A vulnerability in Cisco Unified Communications Manager (Unified CM), Cisco Unified Communications Manager Session     Management Edition (Unified CM SME), Cisco Unified Communications Manager IM & Presence Service (Unified CM IM&P),     Cisco Unity Connection, and Cisco Webex Calling Dedicated Instance could allow an unauthenticated, remote attacker     to execute arbitrary commands on the underlying operating system of an affected device. This vulnerability is due to     improper validation of user-supplied input in HTTP requests. An attacker could exploit this vulnerability by sending     a sequence of crafted HTTP requests to the web-based management interface of an affected device. A successful     exploit could allow the attacker to obtain user-level access to the underlying operating system and then elevate     privileges to root. (CVE-2026-20045)

Please see the included Cisco BID and Cisco Security Advisory for more information.

According to its self-reported version, Cisco Unity Connection is affected by a remote code execution vulnerability:

  - A vulnerability in Cisco Unified Communications Manager (Unified CM), Cisco Unified Communications Manager Session     Management Edition (Unified CM SME), Cisco Unified Communications Manager IM & Presence Service (Unified CM IM&P),     Cisco Unity Connection, and Cisco Webex Calling Dedicated Instance could allow an unauthenticated, remote attacker     to execute arbitrary commands on the underlying operating system of an affected device. This vulnerability is due to     improper validation of user-supplied input in HTTP requests. An attacker could exploit this vulnerability by sending     a sequence of crafted HTTP requests to the web-based management interface of an affected device. A successful     exploit could allow the attacker to obtain user-level access to the underlying operating system and then elevate     privileges to root. (CVE-2026-20045)

Please see the included Cisco BID and Cisco Security Advisory for more information.

ID	Name	Product	Family	Severity
296365	Cisco Unified Communications Manager IM & Presence Service Remote Code Execution (cisco-sa-voice-rce-mORhqY4b)	Nessus	CISCO	critical
296364	Cisco Unified Communications Manager (CUCM) Remote Code Execution (cisco-sa-voice-rce-mORhqY4b)	Nessus	CISCO	critical
295030	Cisco Unity Connection Remote Code Execution (cisco-sa-voice-rce-mORhqY4b)	Nessus	CISCO	critical

Detections

Analytics

CVE-2026-20045

high

Tenable Plugins

critical

critical

critical