CVE-2025-20309: Cisco Unified CM Flaw Enables Remote Root Access
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A newly discovered vulnerability in Cisco’s Unified Communications Manager platforms has drawn significant attention. Tracked as CVE-2025-20309 and carrying a maximum severity score, this flaw opens the door to full system compromise without authentication. While Cisco has issued patches, the potential impact makes understanding this issue essential for all affected organizations.
What Is CVE-2025-20309?
CVE-2025-20309 (CVSS 10.0) stems from static root account credentials that were originally embedded for development purposes. These credentials, hardcoded and immutable, allow anyone with knowledge of them to remotely access a vulnerable device via SSH – no authentication checks required.
CVE-2025-20309 in Cisco Unified Communications Manager (SOCRadar Vulnerability Intelligence)
If exploited, the attacker could log in as the root user and run arbitrary commands, essentially taking complete control of the system. This level of access not only jeopardizes the integrity and confidentiality of the communication platform but also enables deeper lateral movement across the network.
The vulnerability was discovered through Cisco’s internal security testing.
Which Cisco Unified CM Versions Are Affected?
Only a specific range of Engineering Special (ES) releases of Cisco Unified CM and Unified CM Session Management Edition (SME) are vulnerable. These include:
- Unified CM / Unified CM SME versions 15.0.1.13010-1 through 15.0.1.13017-1
It is important to note that these ES releases are not publicly distributed and are only available through Cisco’s Technical Assistance Center (TAC). Regular Service Updates and all other releases, including versions 12.5 and 14, are not impacted.
Has CVE-2025-20309 Been Exploited?
As of now, there are no public reports or observed malicious exploitation of CVE-2025-20309. However, due to the nature of the flaw – allowing remote root access without credentials – it represents a high-value target for threat actors.
Indicators of Compromise (IoCs)
Cisco has provided Indicators of Compromise (IoCs) that administrators can use to determine if their systems may have been accessed.
Specifically, log entries in /var/log/active/syslog/secure showing successful SSH login sessions by the root user are red flags. A command is available (file get activelog syslog/secure) to retrieve these logs for analysis.
Mitigation Steps and Patch Availability
There are no viable workarounds for this vulnerability. The only recommended action is to apply Cisco’s provided patches without delay.
- For affected 15.x ES releases: upgrade to 15SU3 (July 2025) or apply the patch file:
ciscocm.CSCwp27755_D0247-1.cop.sha512
Organizations with active Cisco service contracts can access these updates through their usual channels.
For additional technical details and ongoing updates, refer to the official Cisco advisory.
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Article Link: https://socradar.io/cve-2025-20309-cisco-unified-cm-remote-root-access/