Nx OsOperating system · Cisco
CVE-2024-20291
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 access control list (ACL) programming for port channel subinterfaces of Cisco Nexus 3000 and 9000 Series Switches in standalone NX-OS mode could allow an unauthenticated, remote attacker to send traffic that should be blocked through an affected device. This vulnerability is due to incorrect hardware programming that occurs when configuration changes are made to port channel member ports. An attacker could exploit this vulnerability by attempting to send traffic through an affected device. A successful exploit could allow the attacker to access network resources that should be protected by an ACL that was applied on port channel subinterfaces.
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 confidenceThis vulnerability in Cisco Nexus 3000/9000 Series Switches (standalone NX-OS mode) stems from incorrect hardware programming when port channel member port configurations change. ACLs applied to port channel subinterfaces fail to properly filter traffic due to this programming error, allowing traffic that should be blocked to pass through the device.
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
Nx OsOperating system
= 9.3\(10\)= 9.3\(11\)= 9.3\(12\)CVSS 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
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/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.
-
Check NX-OS versionRun 'show version' and locate the NX-OS release string (e.g., 9.3(10), 9.3(11), or 9.3(12))Affected if The version shown is exactly 9.3(10), 9.3(11), or 9.3(12)
-
Verify device is in standalone NX-OS modeRun 'show system mode' or check 'show version' for mode indication. This vulnerability applies only to standalone NX-OS, not ACI modeAffected if Device is running standalone NX-OS mode (not ACI)
-
Identify port channel subinterfaces with ACLsRun 'show ip interface' and 'show running-config' to locate any ACLs (access-lists) applied to port channel subinterfaces using the 'ip access-group' commandAffected if ACLs are applied to port channel subinterfaces (e.g., 'interface Port-channelX.Y')
-
Check for port channel member port configuration changesRun 'show logging logfile | include Port-channel' or review recent configuration changes to identify if any member port add/remove/modify operations occurred after ACLs were appliedAffected if Configuration changes to port channel member ports have been made after ACLs were applied to the port channel subinterface
A user is affected if they run NX-OS version 9.3(10), 9.3(11), or 9.3(12) in standalone mode and have ACLs applied to port channel subinterfaces that have had member port configuration changes.
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 dataMigrate ACLs from port channel subinterfaces to physical member interfaces or the parent port channel interface, and avoid making configuration changes to port channel member ports after ACL application.
Fix this in Nx Os
Scoped from the published advisory
- Consultation6.0 h
- Implementation12.0 h
- Testing8.0 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 $8,448.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2024-20291 — 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-2024-20291 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