CatalystHardware / appliance · Cisco
CVE-2005-1942
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 switches that support 802.1x security allow remote attackers to bypass port security and gain access to the VLAN via spoofed Cisco Discovery Protocol (CDP) messages.
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 · high confidenceCisco switches with 802.1x port security can be bypassed by remote attackers sending spoofed Cisco Discovery Protocol (CDP) messages. The attack allows unauthorized access to the VLAN by tricking the switch into trusting fraudulent CDP advertisements, circumventing the 802.1x authentication controls.
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
CatalystHardware / appliance
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
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:L/Au:N/C:P/I:P/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.
-
Confirm Cisco Catalyst switch model and firmware versionUse 'show version' command on the switch CLI to identify the switch model and running IOS versionAffected if The device is a Cisco Catalyst switch running any firmware version - all versions are affected per CVE scope
-
Verify 802.1x port-based authentication is configuredUse 'show dot1x all' or 'show running-config | include dot1x' to check if 802.1x is enabled on any portsAffected if 802.1x authentication is actively configured on switch ports - this is the security control being bypassed
-
Check CDP protocol status on switch portsUse 'show cdp neighbors' and 'show cdp interface' to see if CDP is globally enabled or running on specific portsAffected if CDP is enabled on ports, especially on access ports where untrusted devices connect - this is the attack vector
-
Identify ports with both 802.1x and CDP simultaneously enabledCross-reference 'show dot1x interface' output with 'show cdp interface' output per port to find ports running both protocolsAffected if Ports have both 802.1x authentication AND CDP enabled - creating the condition where CDP spoofing can bypass 802.1x
-
Check for CDP packet filtering or port security settingsUse 'show run interface [interface-id]' to inspect per-port CDP configuration and any access control settingsAffected if CDP packets are permitted on ports without additional filtering or validation - the switch trusts CDP advertisements without verification
A Cisco Catalyst switch is affected if it has 802.1x authentication enabled concurrently with CDP protocol running on the same ports, allowing attackers to spoof CDP messages to bypass 802.1x VLAN access controls.
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 Cisco switch firmware to versions that address CDP spoofing vulnerabilities, or disable CDP on untrusted ports if not required, and implement additional VLAN access controls.
Fix this in Catalyst
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 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 $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2005-1942 — 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-2005-1942 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