CVE-2024-20496
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 UDP packet validation code of Cisco SD-WAN vEdge Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected system. This vulnerability is due to incorrect handling of a specific type of malformed UDP packet. An attacker in a machine-in-the-middle position could exploit this vulnerability by sending crafted UDP packets to an affected device. A successful exploit could allow the attacker to cause the device to reboot, resulting in a DoS condition on the affected system.
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 confidenceA vulnerability exists in the UDP packet validation code of Cisco SD-WAN vEdge Software. An attacker positioned as a machine-in-the-middle can send specific malformed UDP packets to cause the device to reboot, resulting in denial of service. The vulnerability stems from incorrect handling of a particular UDP packet type during validation.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
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
- Adjacent
- Complexity
- High
- Privileges
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:A/AC:H/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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Identify vEdge devices in your environmentLocate Cisco SD-WAN vEdge routers or virtual appliances by reviewing network topology documentation, inventory systems, or using 'show version' CLI command on suspect devicesAffected if The device is a Cisco SD-WAN vEdge model running Cisco vEdge OS
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Check the installed vEdge software versionExecute 'show version' on the vEdge device or query your Cisco SD-WAN vManage inventory to retrieve the running software versionAffected if The installed version falls within the vulnerable version range for CVE-2024-20496 (compare your version to Cisco's official advisory for exact affected releases)
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Verify UDP validation is exposed to adjacent attackersReview network segmentation and access control lists (ACLs) protecting the vEdge device. Check if UDP ports are open to untrusted network segments. Use 'show interface' and 'show control connections' to assess exposed UDP pathsAffected if UDP traffic can reach the vEdge device from an adjacent network segment where an attacker could position themselves as MITM
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Confirm the device is reachable on UDP transportUse 'show vmanage connections' or review vEdge transport interface configuration to determine if UDP-based transport is enabled (this is the typical SD-WAN control plane protocol)Affected if The vEdge device uses UDP transport for SD-WAN control connections, exposing the UDP validation code path
You are affected if you have a Cisco SD-WAN vEdge device running a vulnerable software version with UDP transport exposed to an adjacent attacker capable of MITM positioning.
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 Cisco-provided software update/patch for CVE-2024-20496 to affected vEdge devices. As an interim control, restrict network access to limit adjacent attackers and implement network segmentation to reduce MITM exposure.
- Consultation3.0 h
- Implementation3.0 h
- Testing3.0 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 $3,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2024-20496 — 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-2024-20496 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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