VulnerabilityPublished 2 Oct 2024Updated 4 Jun 2025

CVE-2024-20498: Cisco Meraki MX Firmware · Double Free

Affects Cisco Meraki MX FirmwareSource CVE Database V5

Not known to be exploited · CVSS 8.6 High.

Data as of 26 Oct 2026, 12:54 UTC

CVSS 3.1 base score

8.6High

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

EPSS: 0.5% chance of exploitation in 30 days – higher than 42% 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:H

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

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: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

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 or the CVSS exploit maturity 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

Organizations should immediately assess their deployment of Cisco Meraki MX and Z Series Teleworker Gateway devices to determine exposure. Specific mitigation steps include: 1) Monitoring Cisco’s official advisories for firmware updates or patches addressing CVE-2024-20498 and applying them promptly once available. 2) Implementing network-level protections such as rate limiting and filtering to restrict or block suspicious HTTPS requests targeting the VPN server, thereby reducing the risk of exploitation. 3) Employing intrusion detection and prevention systems (IDS/IPS) tuned to detect anomalous SSL VPN session establishment patterns indicative of exploitation attempts. 4) Enhancing VPN server logging and monitoring to quickly identify and respond to service restarts or unusual connection failures. 5) Considering temporary alternative remote access solutions or failover mechanisms to maintain business continuity during patch deployment. 6) Educating IT staff on the vulnerability’s characteristics to improve incident response readiness. Given the automatic recovery behavior, ensuring rapid detection and mitigation of sustained attacks is critical to minimize downtime.

Description

Multiple vulnerabilities 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. These vulnerabilities are due to insufficient validation of client-supplied parameters while establishing an SSL VPN session. An attacker could exploit these vulnerabilities by sending a crafted HTTPS request to the VPN server of an affected device. A successful exploit could allow the attacker to cause the Cisco AnyConnect VPN server to restart, resulting in the failure of the established SSL VPN connections and forcing remote users to initiate a new VPN connection and reauthenticate. A sustained attack could prevent new SSL VPN connections from being established. 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 business continuity and remote workforce productivity. Many enterprises and public sector entities in Europe use Cisco Meraki MX and Z Series devices to provide secure VPN access for remote employees, especially in the context of hybrid work models. A successful DoS attack could interrupt access to corporate networks, critical applications, and data, delaying operations and potentially causing financial and reputational damage. Sectors such as finance, healthcare, government, and critical infrastructure, which heavily depend on secure and reliable VPN connectivity, are particularly vulnerable. Additionally, the disruption of VPN services could hinder compliance with data protection regulations like GDPR if it impacts timely access to data or incident response capabilities. While the vulnerability does not allow data theft or manipulation, the availability impact alone can have cascading effects on operational resilience and incident management.

References

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

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 6 Jul 2025, 21:40 UTC

Technical details

References

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