Network Admission ControlApplication · Cisco
CVE-2006-4430
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 · uneditedThe Cisco Network Admission Control (NAC) 3.6.4.1 and earlier allows remote attackers to prevent installation of the Cisco Clean Access (CCA) Agent and bypass local and remote protection mechanisms by modifying (1) the HTTP User-Agent header or (2) the behavior of the TCP/IP stack. NOTE: the vendor has disputed the severity of this issue, stating that users cannot bypass authentication mechanisms.
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 confidenceThis CVE affects Cisco Network Admission Control (NAC) 3.6.4.1 and earlier versions. The vulnerability allows remote attackers to prevent installation of the Cisco Clean Access (CCA) Agent by modifying either the HTTP User-Agent header or TCP/IP stack behavior, thereby bypassing local and remote NAC protection mechanisms.
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
Network Admission ControlApplication
<= 3.6.4.1
Network Admission Control Manager And Server System SoftwareApplication
= 3.3= 3.3.1= 3.3.2= 3.3.3= 3.3.4= 3.3.5= 3.3.6= 3.3.7= 3.3.8= 3.3.9= 3.4= 3.4.1CVSS 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
- Partial
- Availability
- None
AV:N/AC:L/Au:N/C:N/I:P/A:N
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.
-
Identify Cisco NAC deploymentReview network infrastructure documentation or enumerate network devices to determine if Cisco Network Admission Control (NAC) or Cisco Clean Access (CCA) is deployed in the environmentAffected if Cisco NAC/CCA software is deployed and the version is at or below 3.6.4.1 for NAC, or matches any of these versions for Manager And Server System Software: 3.3, 3.3.1, 3.3.2, 3.3.3, 3.3.4, 3.3.5, 3.3.6, 3.3.7, 3.3.8, 3.3.9, 3.4, or 3.4.1
-
Determine NAC software versionAccess the Cisco Clean Access Manager web interface or check the version via CLI using 'show version' or similar command on the NAC appliance, or check the installed CCA agent version on managed endpointsAffected if The installed version matches or is below 3.6.4.1 for NAC, or equals any of the specific Manager And Server versions listed (3.3.x through 3.4.1)
-
Confirm NAC agent enforcement is activeCheck whether the Cisco Clean Access agent is configured to enforce network admission controls on endpoints, verify agent policy settings in the CCA Manager console or check for CCA agent processes running on client systemsAffected if The CCA agent enforcement is enabled and the underlying NAC version is in the affected range
The environment is affected if Cisco NAC or CCA software is deployed with a version at or below 3.6.4.1 (or matching any of the specific Manager versions 3.3.x-3.4.1) and the NAC agent enforcement feature is active.
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 dataUpgrade to a patched version of Cisco NAC/CCA if available; otherwise, consider replacing with current NAC solutions as Cisco Clean Access has reached end-of-life. Network segmentation can provide additional defense-in-depth.
Fix this in Network Admission Control
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2006-4430 — 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-2006-4430 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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
- No spam, self-promotion, credentials, or personal data