CVE-2025-20281
About
A vulnerability in a specific API of Cisco ISE and Cisco ISE-PIC could allow an unauthenticated, remote attacker to execute arbitrary code on the underlying operating system as root. The attacker does not require any valid credentials to exploit this vulnerability.
This vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by submitting a crafted API request. A successful exploit could allow the attacker to obtain root privileges on an affected device.
Rainforest analyst review
Cisco Identity Services Engine exposes an API that insufficiently validates user-supplied input, letting an unauthenticated remote attacker submit a crafted request that executes arbitrary code on the underlying operating system as root. No credentials are needed and the flaw sits in a network-reachable API, so a single request yields the highest privilege on the appliance, with scope extending beyond the vulnerable component itself.
ISE is the network access control and policy engine that decides which devices and users get onto the network and with what privileges, so root on ISE undermines the authentication fabric of the entire enterprise, an ideal position for lateral movement and persistence. Cisco disclosed it as critical with a maximum score, and it was quickly added to CISA's KEV list amid reports of active exploitation attempts against internet-reachable deployments. Apply the fixed ISE releases without delay, noting that Cisco's guidance required specific patch versions rather than hot fixes for full remediation. Structurally, ISE administration should never be reachable from untrusted networks; restrict management access and review logs for anomalous API calls and new root-level activity.
References
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ise-unauth-rce-ZAd2GnJ6
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-20281
- https://www.zerodayinitiative.com/blog/2025/7/24/cve-2025-20281-cisco-ise-api-unauthenticated-remote-code-execution-vulnerability
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Frequently asked questions
What is CVE-2025-20281?
A vulnerability in a specific API of Cisco ISE and Cisco ISE-PIC could allow an unauthenticated, remote attacker to execute arbitrary code on the underlying operating system as root. The attacker does not require any valid credentials to exploit this vulnerability. This vulnerability is due to insufficient validation of user-supplied input.
How severe is CVE-2025-20281?
CVE-2025-20281 carries a CVSS 3.1 base score of 10, rated critical. On the Rainforest Risk Index — which weighs the severity alongside how easy the flaw is to reach and how broad its impact is — it scores 100 out of 100, in the critical band.
How is CVE-2025-20281 exploited?
According to the CVSS vector (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H): attack vector Network, attack complexity Low, privileges required None, user interaction None. Impact on confidentiality High, integrity High and availability High.
Which products are affected by CVE-2025-20281?
Public advisories list the following as affected: identity services engine, identity services engine passive identity connector. Check the references on this page for the exact versions each vendor confirms.
How do I fix CVE-2025-20281?
Apply the fix the vendor published — the references on this page link to the primary advisories and patches. When patching can't happen right away, reduce the exposure of the affected component and watch it for exploitation attempts. Rainforest customers see this vulnerability correlated to their own assets and prioritized by real exposure, not by score alone.
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