Cisco has released urgent security updates to remediate a high-severity vulnerability in its Integrated Management Controller (IMC) virtual keyboard video monitor (vKVM) module that could allow unauthenticated, remote attackers to hijack sessions and redirect users to malicious websites.
The flaw, tracked as CVE-2025-20317, carries a CVSS base score of 7.1 and affects a wide range of Cisco UCS servers, appliances, and Catalyst uCPE platforms.
No workarounds exist, making prompt patching critical to prevent credential theft and targeted phishing campaigns.
Vulnerability Details and Attack Scenario
The vulnerability stems from insufficient validation of vKVM endpoints within the Cisco IMC interface. When a user accesses the remote console through the vKVM client, specially crafted links can exploit the weakness and redirect the user to an attacker-controlled site.
Because the redirect occurs within the trusted IMC management session, victims may be unaware they have left the legitimate interface.
Once redirected, attackers can deploy phishing pages mimicking Cisco login prompts and capture administrator credentials or session tokens.
Exploitation requires no prior authentication and can be delivered via email or chat with a malicious URL, making it an attractive vector for widespread spear-phishing attacks against data center administrators.
Key attack characteristics include:
- No authentication required to trigger the redirect.
- Victims remain within the IMC session window, reducing suspicion.
- Phishing pages can clone Cisco login flows for stealth credential harvesting.
- Delivery via commonplace channels such as email, messaging, or intranet.
Affected Products and Impacted Releases
All Cisco products running a vulnerable IMC release are at risk, irrespective of specific device configurations. Key impacted platforms include:
- Catalyst 8300 Series Edge uCPE (IMC included in NFVIS).
- UCS Manager Software and its embedded vKVM client.
- UCS B-Series Blade Servers and X-Series Modular Systems.
- UCS C-Series M6, M7, and M8 Rack Servers.
- UCS E-Series M6 Servers.
In addition, numerous Cisco appliances built on UCS C-Series hardware inherit the vulnerability if they expose the IMC UI.
Affected appliances include Application Policy Infrastructure Controller (APIC) servers, DNA Center, HyperFlex nodes, Nexus Dashboard Appliances, Secure Malware Analytics Appliances, and more.
Administrators should note:
- Certain legacy models (UCS C-Series M5, UCS E-Series M3, ENCS 5000) are not affected.
- Fixed software versions vary by platform; consult the advisory for exact releases.
- Upgrades must align with licensing terms and hardware compatibility.
Mitigations
No configuration changes or temporary workarounds mitigate this vulnerability. Cisco recommends that all customers with valid service contracts download and install the provided free security updates through their usual channels.
For appliances lacking a direct upgrade path—such as specific Telemetry Broker, IEC6400 Edge Compute, Secure Endpoint, and Secure Firewall Management Center platforms—Cisco has released specialized firmware images and hotfix instructions to apply IMC patches safely without requiring full system replacement.
Organizations without current service agreements should contact Cisco TAC to obtain the necessary upgrades.
Customers must supply the product serial number and reference advisory ID cisco-sa-ucs-vkvmorv-CnKrV7HK to receive entitlement verification.
Before upgrading, verify hardware compatibility, memory requirements, and licensing entitlements to ensure seamless deployment.
Cisco’s Product Security Incident Response Team (PSIRT) reports no active exploitation or public announcements related to the vulnerability as of the advisory’s publication on August 27, 2025.
However, given the ease of exploitation and the absence of any interim mitigations, timely patching is critical to defend against potential red-team activity and credential phishing campaigns.
Maintaining current IMC firmware and monitoring Cisco advisories will help protect vital compute and virtualization infrastructure from rising remote-code and credential theft threats.
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