Identity Services EngineApplication · Cisco
CVE-2025-20152
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA vulnerability in the RADIUS message processing feature of Cisco Identity Services Engine (ISE) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling of certain RADIUS requests. An attacker could exploit this vulnerability by sending a specific authentication request to a network access device (NAD) that uses Cisco ISE for authentication, authorization, and accounting (AAA). A successful exploit could allow the attacker to cause Cisco ISE to reload.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA vulnerability in Cisco ISE's RADIUS message processing allows an unauthenticated remote attacker to send specially crafted RADIUS authentication requests through a network access device (NAD) to the ISE server, causing the ISE device to reload due to improper handling of these requests.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Identity Services EngineApplication
= 3.4.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Verify Cisco ISE is installedRun 'show version' in the ISE CLI or check the ISE admin web interface under Administration > System > Licensing to confirm the product is deployedAffected if Cisco Identity Services Engine software is present in the environment
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Check installed ISE versionExecute 'show version' in the ISE CLI or view the version in the ISE web UI (typically displayed on the dashboard or under Operations > Reports)Affected if The displayed version is exactly 3.4.0
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Confirm RADIUS service is enabledIn the ISE web UI, navigate to Administration > Network Resources > Network Access Devices (NADs) or check RADIUS server settings; in CLI, run 'show radius server' to verify RADIUS is configured and activeAffected if RADIUS authentication service is enabled and the ISE is accepting RADIUS requests
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Check RADIUS port exposureRun 'show listening-port' or check network firewall rules to verify ports 1812/1813 (or legacy 1645/1646) are open and accessible from network devicesAffected if RADIUS ports are open and reachable from network access devices
You are affected if Cisco ISE version 3.4.0 is running and RADIUS authentication service is enabled and exposed to network access devices.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply the vendor patch when available; until then, consider implementing network-level filtering or access controls on RADIUS traffic between NADs and Cisco ISE to limit exposure to untrusted sources.
Fix this in Identity Services Engine
Scoped from the published advisory
- Consultation4.0 h
- Implementation3.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,680.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-20152 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-20152 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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