Cisco Unified Communications Manager Static SSH Credentials Vulnerability

TL;DR 📌

• 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 log in to an affected device using the root account, which has default, static credentials that cannot be changed or deleted. This vulnerability is due to the presence of static user credentials for…
• No fixed release listed yet; apply mitigations and monitor.
• Workarounds are documented in the advisory.
• CVEs: CVE-2025-20309.

What happened 🕵️‍♂️

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 log in to an affected device using the root account, which has default, static credentials that cannot be changed or deleted.

This vulnerability is due to the presence of static user credentials for the root account that are reserved for use during development. An attacker could exploit this vulnerability by using the account to log in to an affected system. A successful exploit could allow the attacker to log in to the affected system and execute arbitrary commands as the root user.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

Affected products 🖥️

This vulnerability affects Cisco Unified CM and Unified CM SME Engineering Special (ES) releases 15.0.1.13010-1 through 15.0.1.13017-1, regardless of device configuration.

Note: ES releases are limited fix releases that are distributed only by the Cisco Technical Assistance Center (TAC).

For information about which Cisco software releases are vulnerable, see the Fixed Software ["#fs"] section of this advisory.

Fixed software 🔧

Upgrade to the first fixed release in your train (or later):

Workarounds 🧯

There are no workarounds that address this vulnerability.

Risk in context 🎯

Use vendor CVSS for prioritization. Consider exposure and asset criticality.

Fast facts ⚡

• Advisory: cisco-sa-cucm-ssh-m4UBdpE7
• Initial release: 2025-07-02T16:00:00 UTC
• Last updated: 2025-07-02T16:00:00 UTC

For leadership 🧭

Executive summary. A small set of Cisco Unified CM and Unified CM SME Engineering Special releases contain a fixed, undeletable root SSH login that grants full root access with no authentication of the attacker’s own. Any system running the affected 15.0.1.13010-1 through 15.0.1.13017-1 builds should be identified and remediated immediately, as this carries the maximum severity rating and no workaround exists.

Why it matters:

• The static account is for the root user on Unified CM and Unified CM SME, meaning a successful login gives full command execution on the call-processing platform, not a limited service account.
• The credentials cannot be changed or deleted by the customer, so exposed systems stay vulnerable until the software is upgraded — there is no configuration fix.
• This affects only Engineering Special (ES) releases 15.0.1.13010-1 through 15.0.1.13017-1, distributed via Cisco TAC, so exposure is limited to environments that received one of these limited-fix builds regardless of how the device is otherwise configured.
• No workaround is documented, so mitigating controls such as disabling a feature or restricting configuration will not close this off.

Now / Next / Later:

• Now: Check whether any Unified CM or Unified CM SME systems are running an ES build in the range 15.0.1.13010-1 through 15.0.1.13017-1, since these are distributed only through TAC and may not be widely tracked in normal patch inventories.
• Next: Upgrade any affected systems to a fixed release identified in the advisory during your next change window, and restrict SSH reachability to Unified CM management interfaces in the meantime.
• Later: Add a check for TAC-distributed Engineering Special builds to your asset and patch inventory process so limited-fix releases with known issues like this are tracked the same way as general availability software.