dbcve.org
Meraki Mx65 FirmwareOperating system · Cisco

CVE-2024-20509

MEDIUM · 5.9 CVSS v3.1 Published 2024-10-02
Fix available
A fix is available. Upgrade to 18.211.2 or later.
See remediation →
68/100
Remediation priority · Elevated
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 hijack an AnyConnect VPN session or cause a denial of service (DoS) condition for individual users of the AnyConnect VPN service on an affected device. This vulnerability is due to weak entropy for handlers that are used during the VPN authentication process as well as a race condition that exists in the same process. An attacker could exploit this vulnerability by correctly guessing an authentication handler and then sending crafted HTTPS requests to an affected device. A successful exploit could allow the attacker to take over the AnyConnect VPN session from a target user or prevent the target user from establishing an AnyConnect VPN session with the affected device.

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 vulnerability in Cisco AnyConnect VPN server on Meraki MX and Z Series devices stems from weak entropy in authentication handlers combined with a race condition. An unauthenticated remote attacker can guess the authentication handler and send crafted HTTPS requests to either hijack an existing VPN session or cause a DoS by preventing users from connecting.

MitigationApply the vendor-supplied firmware/software update from Cisco that addresses the weak entropy and race condition in the AnyConnect VPN authentication handlers.

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
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:H/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 device model
    Locate the Meraki model number (MX64, MX65, Z4, Z4c, Z3, Z3c, VMX, or MX600) from the physical device label or Meraki Dashboard device inventory
    Affected if Device is any of these eight models and is running vulnerable firmware
  2. Check installed firmware version
    Access Meraki Dashboard, navigate to the device status page, or use the Meraki API to retrieve the current firmware version
    Affected if Firmware version is greater than or equal to 17.6.0 but less than 18.211.2 for MX64/MX65, or greater than or equal to 16.2 but less than 18.211.2 for Z4/Z4c/Z3/Z3c/VMX/MX600
  3. Verify AnyConnect VPN is enabled
    Log into Meraki Dashboard and navigate to Security & SD-WAN > AnyConnect VPN or check the VPN configuration settings to determine if the AnyConnect VPN server feature is configured and enabled
    Affected if AnyConnect VPN server is enabled on the device

Device is affected if it is an MX64, MX65, Z4, Z4c, Z3, Z3c, VMX, or MX600 running firmware between the minimum shown version and 18.211.2, with AnyConnect VPN server turned on.

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/software update from Cisco that addresses the weak entropy and race condition in the AnyConnect VPN authentication handlers.

Recommended fix Moderate confidence

18.211.2 or later

  1. Download the fixed firmware version (18.211.2 or later) from the Cisco Meraki dashboard or support portal
  2. Review the Meraki MX or Z Series upgrade guide for any pre-upgrade requirements
  3. Back up the current device configuration
  4. Schedule a maintenance window as the upgrade may cause a brief service interruption
  5. Upload and apply the firmware upgrade through the Meraki dashboard or via the device CLI
  6. Verify the device upgraded successfully and all VPN services are functioning normally
  7. Confirm the running firmware version is 18.211.2 or later

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
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
Get the upgrade done

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

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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-2024-20509 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