CVE-2024-20502Network attack vector

VPN connection denial via SSL session exhaustion

Published Oct 2, 2024 · Updated Jun 4, 2025

Resource exhaustion in Cisco Meraki MX Firmware allows remote attackers to block new AnyConnect VPN sessions via crafted HTTPS requests. The AnyConnect VPN server allocates or retains session-establishment resources without sufficient management as it processes a series of attacker-controlled HTTPS requests. Exposure requires AnyConnect VPN to be enabled; the service recovers after traffic stops, existing sessions continue, and only new connections are refused.

CVSS severity5.8
Medium
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Cisco Meraki MX Firmware allows remote attackers to block new AnyConnect VPN sessions via crafted HTTPS requests. The AnyConnect VPN server allocates or retains session-establishment resources without sufficient management as it processes a series of attacker-controlled HTTPS requests. Exposure requires AnyConnect VPN to be enabled; the service recovers after traffic stops, existing sessions continue, and only new connections are refused.

The record

CVE
CVE-2024-20502
Published
Oct 2, 2024
Updated
Jun 4, 2025
Vendor
ClamAV
Product
Cisco Meraki MX Firmware
Classifications
CWE-400, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 2, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0
  2. Affected versionversion=N/A

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Meraki MX Firmwareversion=0; version=N/A
ClamAV · Cisco Meraki Z1 Firmwareversion=0

Published CVSS scores

5.8Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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