Summary
CVE-2025-20281 is a critical flaw in Cisco ISE/ISE-PIC that allows unauthenticated remote attackers to execute commands as root. Affecting 3.3 and 3.4 releases, it’s rated CVSS 10.0 with no workarounds and public exploits available. Immediate patching (3.3 Patch 6, 3.4 Patch 2) is essential to avoid full system compromise.
Urgent Actions Required
Upgrade Cisco ISE 3.3 to Patch 6 and Cisco ISE 3.4 to Patch 2 as soon as possible.
No workarounds are available, so patching is the only effective mitigation. Monitor Cisco advisories and system logs closely for any unusual or suspicious API activity.
Which Systems Are Vulnerable to CVE-2025-20281?
Technical Overview
- Vulnerability Type: Remote Code Execution via Improper Input Validation in API
- Affected Software/Versions:
- Cisco Identity Services Engine (ISE) 3.3 (before Patch 6)
- Cisco Identity Services Engine (ISE) 3.4 (before Patch 2)
- Cisco ISE-PIC (same versions as above)
- Attack Vector: Network (API request over HTTP/HTTPS)
- CVSS Score: 10.0
- CVSS Vector: CVSS:3.1
- Attack Vector: Network
- Attack Complexity: Low
- Privileges Required: None
- User Interaction: None
- Patch Availability: Yes - fixed in Cisco ISE 3.3 Patch 6 and 3.4 Patch 2[1]
How Does the CVE-2025-20281 Exploit Work?
The attack typically follows these steps:
What Causes CVE-2025-20281?
Vulnerability Root Cause:
The flaw comes from poor input validation in a public API of Cisco ISE/ISE-PIC. Attackers can send crafted requests to inject OS commands, which the system runs with root privileges, resulting in full remote code execution.
How Can You Mitigate CVE-2025-20281?
No official workarounds are currently available for this vulnerability. The only effective mitigation is to apply Cisco’s security updates.
Upgrade to Cisco ISE/ISE-PIC 3.3 Patch 6 or 3.4 Patch 2 as soon as possible to fully address the issue.
Which Assets and Systems Are at Risk?
Asset Types Affected:
- Cisco Identity Services Engine (ISE) appliances
- Cisco ISE-PIC (Passive Identity Connector) appliances
Business-Critical Systems at Risk:
- Network Access Control platforms – core to managing user/device authentication in enterprise networks
- Identity and Policy Management systems – central for enforcing security and compliance policies
- Integrated IT/security environments – where Cisco ISE is tied to Active Directory, VPNs, or security appliances
Exposure Level:
- Internet-exposed Cisco ISE/ISE-PIC systems – most at risk due to remote unauthenticated exploitability
- Internal enterprise networks – also vulnerable if attackers gain network foothold and can reach the API endpoint
Will Patching CVE-2025-20281 Cause Downtime?
Patch application impact: Patch application may require standard upgrade and reboot procedures; organizations should plan maintenance windows accordingly.
Remediation & Response
Patch/Upgrade Instructions:
- Customers should upgrade to the fixed releases specified in the official Cisco advisory.[1]
Remediation Timeline:
- Cisco strongly recommends applying the patch immediately.
- Until upgraded, affected Cisco ISE appliances remain exposed to attempted exploitation.
Rollback Plan:
If the upgrade introduces operational issues, revert to the previous known stable Cisco ISE release and schedule reapplication of the patched version once validated.
Incident Response Considerations:
Admins should review system and access logs for signs of suspicious API activity and ensure deployments are fully patched.
Where Can I Find More Information on CVE-2025-49706?
CVSS Breakdown Table
| Metric | Value | Description |
|---|---|---|
| Base Score | 10.0 | Critical severity, maximum impact and exploitability |
| Attack Vector | Network | Vulnerable remotely over HTTP/HTTPS |
| Attack Complexity | Low | Straightforward exploitation: no special conditions required |
| Privileges Required | None | No authentication or privileges needed to exploit |
| User Interaction | None | No user involvement (e.g., no clicks) is necessary |
| Scope | Changed | Exploitation can extend impact beyond the Cisco ISE component |
| Confidentiality Impact | High | Full exposure of sensitive information possible |
| Integrity Impact | High | Allows unauthorized data modification or tampering |
| Availability Impact | High | Successful exploitation can significantly disrupt system availability |
