Cisco ISE Injection Vulnerability CVE-2025-20337

Historical catalog analysis: CISA added this entry on July 28, 2025. The entry reflects catalog information retrieved on August 31, 2026, not a snapshot archived on the inclusion date. Check current vendor guidance before acting.

What the vulnerability is

CVE-2025-20337 is an injection vulnerability affecting Cisco Identity Services Engine (ISE) and Cisco ISE-PIC. The flaw stems from insufficient validation of user-supplied input within a specific API. According to CISA, an attacker could exploit this by submitting a crafted API request, which could lead to remote code execution (RCE) and the acquisition of root privileges on the affected device.

Exposure and applicability

This vulnerability is particularly relevant for healthcare organizations that rely on Cisco ISE for network access control (NAC). In clinical environments, ISE is often used to enforce segmentation between medical devices, guest networks, and servers containing electronic Protected Health Information (ePHI).

Because the vulnerability allows for root-level access, a successful exploit could potentially enable an attacker to bypass these segmentation policies. This increases the risk of lateral movement across the clinical network, where an attacker might move from a compromised low-security zone into restricted areas housing critical patient care systems or health records.

Remediation priorities

Based on our analysis, healthcare security leaders should prioritize the following actions:

1. Inventory and Version Verification: Identify all instances of Cisco ISE and Cisco ISE-PIC within the environment. Security administrators should verify if their specific deployment utilizes the affected API mentioned in vendor advisories.
2. Apply Vendor Mitigations: Prioritize the application of official patches or mitigations provided by Cisco to address the input validation failure. This is the primary method for preventing initial access via this vector.
3. Review Network Access Controls: While patching addresses the root cause, network teams should review existing firewall rules and access control lists (ACLs) that protect the ISE management interface to ensure it is not exposed to untrusted networks.
4. Cloud Service Alignment: For organizations utilizing Cisco ISE via cloud services, follow applicable guidance regarding BOD 22-01 to ensure service providers have addressed the vulnerability.

How to validate remediation

To verify that exposure has been reduced, administrators should:
* Confirm Patch Application: Verify through the system dashboard or command line that the version currently running includes the fix for CVE-2025-20337.
* Audit API Access: Review logs for unauthorized or malformed API requests targeting the affected endpoint to ensure no exploitation occurred prior to patching.
* Configuration Audit: Confirm that management interfaces are restricted to authorized administrative subnets, reducing the reachable attack surface.

Limits and open questions

It remains unknown whether this vulnerability has been utilized in active ransomware campaigns. Furthermore, while CISA has added this to the Known Exploited Vulnerabilities catalog, the specific details of the “crafted API request” are managed by the vendor; therefore, organizations must rely on official Cisco advisories for the exact technical triggers.

Applying a patch reduces the likelihood of exploitation via this specific injection flaw but does not eliminate all risks associated with network access control. Residual risk remains if other unpatched vulnerabilities exist or if administrative credentials have already been compromised.

Source and editorial note

CVE-2025-20337: Cisco Identity Services Engine Injection Vulnerability · Source date: July 28, 2025 · Retrieved August 31, 2026.

Material facts are tied to the cited primary source. Recommendations are independent defensive analysis unless attributed to the source. Confirm consequential decisions against current authoritative guidance.

Archive date: July 31, 2025. The displayed post date is assigned three days after the source date to organize this retrospective archive; it does not mean this site published the analysis then. First published by this site: October 04, 2026 at 01:24 UTC.

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