CVE-2025-20212 Denial of service in Cisco Meraki MX Firmware
An authenticated remote attacker can cause a denial of service in the Cisco AnyConnect VPN server by supplying crafted attributes during SSL session establishment.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-20212?
CVE-2025-20212 is a high-severity denial of service vulnerability in Cisco Meraki MX Firmware, published on 2 Apr 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
A vulnerability in the Cisco AnyConnect VPN server of Cisco Meraki MX and Cisco Meraki Z Series devices could allow an authenticated, remote attacker to cause a denial of service (DoS) condition in the Cisco AnyConnect service on an affected device. To exploit this vulnerability, the attacker must have valid VPN user credentials on the affected device. This vulnerability exists because a variable is not initialized when an SSL VPN session is established. An attacker could exploit this vulnerability by supplying crafted attributes while establishing an SSL VPN session with 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 sessions 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 without manual intervention.
Weakness: CWE-457
Which versions are affected by CVE-2025-20212?
How do I fix CVE-2025-20212?
No fix has been published for CVE-2025-20212 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-20212 being exploited?
There is no known exploitation of CVE-2025-20212 in the wild and no public exploit code.
Sources
Also known as GHSA-mf93-68c7-8cg2.