Ios XeOperating system · Cisco
CVE-2024-20480
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 DHCP Snooping feature of Cisco IOS XE Software on Software-Defined Access (SD-Access) fabric edge nodes could allow an unauthenticated, remote attacker to cause high CPU utilization on an affected device, resulting in a denial of service (DoS) condition that requires a manual reload to recover. This vulnerability is due to improper handling of IPv4 DHCP packets. An attacker could exploit this vulnerability by sending certain IPv4 DHCP packets to an affected device. A successful exploit could allow the attacker to cause the device to exhaust CPU resources and stop processing traffic, resulting in a DoS condition that requires a manual reload to recover.
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 confidenceA remote unauthenticated attacker can exploit improper handling of IPv4 DHCP packets in the DHCP Snooping feature of Cisco IOS XE on SD-Access fabric edge nodes. Sending specially crafted DHCP packets causes high CPU utilization, stopping all traffic processing and requiring a manual device reload to recover.
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
Ios XeOperating system
= 16.1.1= 16.1.2= 16.1.3= 16.2.1= 16.2.2= 16.3.1= 16.3.1a= 16.3.2= 16.3.3= 16.3.4= 16.3.5= 16.3.5bCVSS 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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Check the IOS XE versionExecute 'show version' on the device and note the version number in the output (look for 'Version 16.x.x').Affected if The version matches any of the affected releases: 16.1.1, 16.1.2, 16.1.3, 16.2.1, 16.2.2, 16.3.1, 16.3.1a, 16.3.2, 16.3.3, 16.3.4, 16.3.5, or 16.3.5b.
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Verify DHCP Snooping is enabledExecute 'show ip dhcp snooping' and examine the output. Look for 'Switch DHCP snooping is enabled' or similar status indicating the feature is active.Affected if DHCP Snooping shows as enabled (the vulnerability only triggers when DHCP Snooping is actively running).
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Confirm the device is functioning as an SD-Access fabric edge nodeExecute 'show running-config | include sd-access|fabric edge' or 'show sd-av' if available. Also check the device role in the fabric with 'show fabric zone summary' or similar SD-Access show commands.Affected if The device is configured as an SD-Access fabric edge node (the vulnerability specifically affects this role).
The device is affected if it runs any affected IOS XE version (16.1.1 through 16.3.5b), has DHCP Snooping enabled, and operates as an SD-Access fabric edge node.
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 latest Cisco IOS XE software patches or upgrade to a fixed release. Consider disabling DHCP Snooping if not required, or implement ACLs to filter untrusted DHCP traffic as an interim workaround.
Fix this in Ios Xe
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 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 $5,600.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2024-20480 — 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-2024-20480 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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- Version or environment caveats, and links to real fixes
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