dbcve.org
Meraki Mx65 FirmwareOperating system · Cisco

CVE-2024-20502

HIGH · 7.5 CVSS v3.1 Published 2024-10-02
Fix available
A fix is available. Upgrade to 18.211.2 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
A vulnerability in the Cisco AnyConnect VPN server of Cisco Meraki MX and Cisco Meraki Z Series Teleworker Gateway devices could allow an unauthenticated, remote attacker to cause a DoS condition on an affected device. This vulnerability is due to insufficient resource management while establishing SSL VPN sessions. An attacker could exploit this vulnerability by sending a series of crafted HTTPS requests to the VPN server of an affected device. A successful exploit could allow the attacker to cause the Cisco AnyConnect VPN server to stop accepting new connections, preventing new SSL VPN connections from being established. Existing SSL VPN sessions are not impacted. Note: When the attack traffic stops, the Cisco AnyConnect VPN server recovers gracefully without requiring manual intervention.

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 confidence

This is a denial-of-service vulnerability in the Cisco AnyConnect VPN server component of Cisco Meraki MX and Z Series Teleworker Gateway devices. The vulnerability stems from insufficient resource management during SSL VPN session establishment. An unauthenticated remote attacker can exploit this by sending a series of crafted HTTPS requests to the VPN server, causing resource exhaustion that stops the server from accepting new connections.

MitigationApply the vendor-supplied firmware/security update from Cisco/Meraki when available. In the interim, consider implementing rate limiting on perimeter devices for VPN endpoint traffic and monitor for service availability anomalies.

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
Meraki Mx65 FirmwareOperating system
Affected:>= 17.6.0, < 18.211.2
Meraki Mx64 FirmwareOperating system
Affected:>= 17.6.0, < 18.211.2
Meraki Z4c FirmwareOperating system
Affected:>= 16.2, < 18.211.2
Meraki Z4 FirmwareOperating system
Affected:>= 16.2, < 18.211.2
Meraki Z3c FirmwareOperating system
Affected:>= 16.2, < 18.211.2
Meraki Z3 FirmwareOperating system
Affected:>= 16.2, < 18.211.2
Meraki Vmx FirmwareOperating system
Affected:>= 16.2, < 18.211.2
Meraki Mx600 FirmwareOperating system
Affected:>= 16.2, < 18.211.2

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
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the device model
    Access the Meraki dashboard or check the physical device label to confirm the exact model (MX64, MX65, MX600, Z3, Z3c, Z4, Z4c, or VMX)
    Affected if The device is not one of the listed affected models, then it is not vulnerable to this specific CVE
  2. Check the installed firmware version
    In the Meraki dashboard, go to Organization > Firmware upgrades, or check the device status page to find the current firmware version running on the device
    Affected if The firmware version falls within the affected ranges: >= 17.6.0 and < 18.211.2 for MX devices, or >= 16.2 and < 18.211.2 for Z Series and VMX devices
  3. Verify if AnyConnect SSL VPN is enabled
    In the Meraki dashboard, navigate to Security & SD-WAN > AnyConnect VPN (or VPN > Site-to-site) and confirm whether the AnyConnect VPN feature is turned on for the device
    Affected if AnyConnect VPN is not enabled on the device, then the attack surface for this specific vulnerability does not exist
  4. Check for VPN service availability issues
    Monitor the Meraki dashboard for VPN connection failures, inability to establish new AnyConnect sessions, or service degradation alerts indicating resource exhaustion
    Affected if The device is experiencing unexplained VPN service disruptions or rejecting new connections while the firmware version falls within the affected range and VPN is enabled

The environment is affected if the device is an affected Meraki model (MX64, MX65, MX600, Z3, Z3c, Z4, Z4c, VMX), runs firmware version >= 16.2 (or >= 17.6.0 for MX) but below 18.211.2, and has AnyConnect SSL VPN enabled.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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.

dbcve · scoped
Upgrade available Upgrade to 18.211.2 or later
Fixed in 18.211.2
Interim mitigation

Apply the vendor-supplied firmware/security update from Cisco/Meraki when available. In the interim, consider implementing rate limiting on perimeter devices for VPN endpoint traffic and monitor for service availability anomalies.

Recommended fix High confidence

18.211.2

  1. Log into the Meraki Dashboard and navigate to the device's Network-wide > General page to verify the current firmware version
  2. Review the release notes for firmware version 18.211.2 to confirm compatibility with your specific device model
  3. Schedule a maintenance window for the firmware upgrade (existing SSL VPN sessions will remain active during upgrade)
  4. In the Meraki Dashboard, go to Network-wide > Firmware Upgrades and select the target device(s)
  5. Choose firmware version 18.211.2 or later from the available upgrades and apply the upgrade
  6. Monitor the device status in the Dashboard to confirm the upgrade completes successfully
  7. Verify the device is now running firmware version 18.211.2 or later by checking Network-wide > General

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Meraki Mx65 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,690
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,304.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-20502 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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