Cisco has identified a significant security vulnerability within the Virtual Keyboard Video Monitor (vKVM) component of its Integrated Management Controller (IMC). This flaw, designated as CVE-2025-20317 with a CVSS 3.1 base score of 7.1, allows unauthenticated remote attackers to redirect users of affected devices to malicious websites. Such redirections can be exploited for phishing attacks, potentially leading to unauthorized access to sensitive credentials.
Technical Details:
The vulnerability arises from inadequate endpoint verification in the vKVM’s connection handling code. When a user interacts with a specially crafted link, the vKVM client fails to properly validate the redirection target, enabling attackers to direct users to arbitrary URLs. Given that the IMC interface is frequently utilized for critical system management tasks, compromising its credentials could have extensive repercussions on Cisco UCS infrastructure.
Affected Products:
The vulnerability impacts any Cisco product that exposes the IMC interface with a susceptible vKVM release. Notable affected platforms include:
– UCS B-Series Blade Servers and X-Series Modular Systems
– UCS C-Series M6, M7, M8, and E-Series M6 Rack and Edge Servers
– Catalyst 8300 Series Edge uCPE
– Various Cisco appliances built on preconfigured C-Series servers, such as APIC, DNA Center, HyperFlex, Nexus Dashboard, Secure Endpoint Private Cloud, and Secure Firewall Management Center
Cisco has provided a comprehensive list of affected appliance families in its advisory. Devices operating on fixed IMC firmware or UCS Manager software versions are secure; however, earlier releases remain vulnerable.
Mitigation Measures:
Currently, there are no available workarounds to mitigate CVE-2025-20317. Administrators are urged to apply the security patches provided in the latest software updates. Customers with valid service contracts can download the patched firmware via the Cisco Support and Downloads portal. Those without active contracts should contact Cisco TAC, referencing Advisory ID cisco-sa-ucs-vkvmorv-CnKrV7HK, to obtain critical fixes at no additional cost.
Fixed Releases:
Cisco’s advisory includes detailed tables outlining fixed firmware and software releases for each product line. Key updates include:
– Cisco UCS Manager Software: Updates in versions 4.2 and above (e.g., 4.2(3p), 4.3(6a))
– Cisco IMC on Catalyst 8300 (NFVIS): Auto-upgrade to NFVIS 4.18.1 or later
– UCS C-Series and E-Series Servers: Fixed IMC releases starting from 4.2(3o) and 4.15.2, respectively
– Intersight-Managed Servers: Firmware 5.3(0.250001) and above for B-Series and X-Series
Appliance-specific remediation steps, such as applying ISO firmware updates for the Telemetry Broker or utilizing the Cisco Host Upgrade Utility, are also detailed in the advisory.
Recommendations:
Although there have been no reported public exploitations of this vulnerability, its potential for exploitation and the critical nature of management interfaces necessitate prompt action. Organizations utilizing Cisco UCS infrastructure should:
1. Inventory Assessment: Identify all devices running Cisco IMC or UCS Manager.
2. Version Verification: Compare current firmware/software versions against the advisory’s fixed-release matrix.
3. Immediate Upgrades: Schedule and execute upgrades to patched versions without delay.
4. User Training: Educate administrators and users to avoid interacting with untrusted links.
Given that compromised IMC credentials can facilitate lateral movement and broader system compromise, timely application of these updates is crucial to mitigate potential threats.
