Identity Services Engine SoftwareApplication · Cisco
CVE-2013-5521
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 · uneditedCisco Identity Services Engine does not properly restrict the creation of guest accounts, which allows remote attackers to cause a denial of service (exhaustion of the account supply) via a series of requests within one session, aka Bug ID CSCue94287.
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 confidenceCisco Identity Services Engine (ISE) fails to properly restrict guest account creation within a single session, allowing remote attackers to repeatedly create guest accounts until the account supply is exhausted, causing denial of service.
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 Engine SoftwareApplication
all versionsCVSS 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
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Partial
AV:N/AC:L/Au:N/C:N/I:N/A:P
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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Identify if Cisco ISE is deployedCheck for Cisco ISE processes, services, or installation directories on the system. On network devices, verify if ISE is configured as an authentication/authorization server.Affected if Cisco Identity Services Engine is present and running in the environment
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Verify guest user provisioning is enabledAccess the Cisco ISE administration console and navigate to Guest > Guest Settings, or inspect the ISE configuration via CLI/API for guest user management settings.Affected if Guest user account creation is enabled in Cisco ISE
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Check for rate limiting on guest account creationInspect Cisco ISE configuration for rate limit settings under Guest > Settings > Guest Type configuration, or check for policy elements related to account creation throttling.Affected if No rate limiting or throttling is configured for guest account creation requests
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Check for session-based constraints on guest flowsReview ISE policy configurations for session limits, concurrent session restrictions, or account creation quotas applied to guest user flows.Affected if No session-based constraints or account quotas are enforced on guest user creation
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Review guest account quota limitsCheck the maximum number of guest accounts allowed in the ISE system under Administration > System > Settings > Guest Settings, or verify if account supply limits are defined.Affected if No maximum guest account limits are configured or the system allows unlimited guest account creation
The environment is affected if Cisco ISE is running with guest user creation enabled and without rate limiting, session constraints, or account quota restrictions configured.
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 dataImplement rate limiting or session-based constraints on guest account creation in Cisco ISE; apply vendor patches when available.
Fix this in Identity Services Engine Software
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2013-5521 — 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-2013-5521 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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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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