Cisco Unified CM Vulnerability Allows Remote Attacker to Login As Root User
A severe vulnerability in Cisco Unified Communications Manager (Unified CM) systems could allow remote attackers to gain root-level access to affected devices.
The vulnerability, designated CVE-2025-20309 with a maximum CVSS score of 10.0, affects Engineering Special releases and stems from hardcoded SSH credentials that cannot be modified or removed by administrators.
Key Takeaways
1. CVE-2025-20309 critical severity flaw (CVSS 10.0) with hardcoded SSH root credentials in Cisco Unified CM systems.
2. Only Engineering Special releases 15.0.1.13010-1 through 15.0.1.13017-1 of Cisco Unified CM and Unified CM SME are vulnerable.
3. Remote attackers gain root access without authentication to execute arbitrary commands.
4. Apply patch ciscocm.CSCwp27755_D0247-1.cop.sha512 or upgrade to 15SU3 - no workarounds available.
Critical Root Access Vulnerability (CVE-2025-20309)
The security flaw affects Cisco Unified CM and Unified CM Session Management Edition (SME) Engineering Special releases 15.0.1.13010-1 through 15.0.1.13017-1.
The vulnerability exists due to static user credentials for the root account that were inadvertently left in the system during development phases.
These credentials are classified under CWE-798, representing the use of hard-coded credentials that create an authentication bypass mechanism.
An unauthenticated remote attacker can exploit this vulnerability by utilizing the static root account credentials to establish SSH connections to vulnerable systems.
Once authenticated, the attacker gains complete administrative control over the affected device, enabling the execution of arbitrary commands with root privileges.
The vulnerability requires no user interaction and can be exploited remotely without any authentication prerequisites, making it particularly dangerous for organizations with internet-facing Unified CM deployments.
| Risk Factors | Details |
| Affected Products | Cisco Unified Communications Manager (Unified CM)- Cisco Unified Communications Manager Session Management Edition (Unified CM SME)- Engineering Special (ES) releases 15.0.1.13010-1 through 15.0.1.13017-1 |
| Impact | Remote attacker can log in as root user- Execute arbitrary commands with root privileges |
| Exploit Prerequisites | No authentication required- Remote network access to affected system- Knowledge of static SSH credentials- No user interaction needed |
| CVSS 3.1 Score | 10.0 (Critical) |
Remediation Strategies
Organizations can identify potential exploitation attempts by monitoring system logs for unauthorized root access.
Cisco recommends examining the /var/log/active/syslog/secure file using the command cucm1# file get activelog syslog/secure to detect indicators of compromise.
Suspicious log entries will display successful SSH login attempts by the root user, accompanied by systemd and sshd authentication messages showing session establishment for user root with UID 0.
Cisco has released software updates addressing this vulnerability, with fixed versions available through the 15SU3 release scheduled for July 2025.
Alternatively, administrators can apply the emergency patch file ciscocm.CSCwp27755_D0247-1.cop.sha512 to vulnerable systems.
Importantly, Cisco has confirmed that no workarounds exist for this vulnerability, making immediate patching or system updates the only effective mitigation strategy.
Organizations should prioritize updating affected systems immediately, as the Engineering Special releases are typically deployed in production environments requiring enhanced stability and security.
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