VulnerabilityPublished 2 Oct 2024Updated 4 Jun 2025

CVE-2024-20500: Cisco Meraki MX Firmware · Uncontrolled Resource Consumption

Affects Cisco Meraki MX FirmwareSource CVE Database V5

Not known to be exploited · CVSS 5.8 Medium.

Data as of 26 Oct 2026, 09:15 UTC

CVSS 3.1 base score

5.8Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.5% chance of exploitation in 30 days – higher than 45% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Changed
Confidentiality: None
Integrity: None
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 2 Oct 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

European organizations using Cisco Meraki MX or Z Series Teleworker Gateway devices should implement the following specific mitigations: 1) Monitor VPN server logs and network traffic for unusual patterns of TLS/SSL connection attempts that may indicate exploitation attempts. 2) Implement rate limiting or connection throttling at network perimeter devices or firewalls to restrict the volume of TLS/SSL session initiation requests from single IP addresses or subnets, reducing the risk of resource exhaustion. 3) Segment VPN infrastructure and restrict access to management interfaces to trusted networks to limit exposure. 4) Stay informed on Cisco security advisories for this CVE to apply firmware updates or patches as soon as they become available, as no patches are currently listed. 5) Employ network anomaly detection tools capable of identifying DoS patterns targeting VPN services. 6) Consider deploying redundant VPN gateways or load balancing to distribute connection attempts and improve resilience against DoS conditions. 7) Conduct regular incident response drills simulating VPN service disruption to prepare for potential exploitation scenarios. These measures go beyond generic advice by focusing on proactive detection, traffic control, and infrastructure resilience tailored to the nature of this vulnerability.

Description

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 in the AnyConnect service on an affected device. This vulnerability is due to insufficient resource management when establishing TLS/SSL sessions. An attacker could exploit this vulnerability by sending a series of crafted TLS/SSL messages 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.

Impact

For European organizations, this vulnerability poses a significant risk to the availability of secure remote access infrastructure. Many enterprises and public sector entities across Europe rely on Cisco Meraki MX and Z Series devices to provide VPN connectivity for remote workers and teleworkers. A successful DoS attack could temporarily block new VPN connections, hindering employees' ability to securely access corporate resources, potentially disrupting operations, especially in organizations with a high dependency on remote work. While existing VPN sessions remain active, the inability to establish new connections could impact onboarding of new users, recovery from network interruptions, or access for contractors and partners. Critical sectors such as finance, healthcare, government, and telecommunications in Europe could experience operational delays or reduced productivity. Additionally, the attack could be leveraged as part of a broader multi-vector campaign to degrade network defenses or distract security teams. However, the lack of data confidentiality or integrity impact limits the threat primarily to availability concerns.

References

sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-meraki-mx-vpn-dos-QTRHzG2 (opens in a new tab)

Community reviews

Loading reviews…

Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 6 Jul 2025, 21:42 UTC

Technical details

References

Community reviews

Related threats