CVE-2025-20271: cisco cisco meraki mx firmware Use of Uninitialized Variable

Vulnerability summary

CVE-2025-20271 is a high (CVSS 8.6) Use of Uninitialized Variable vulnerability in cisco cisco meraki mx firmware. EPSS estimates a 0.54% chance of exploitation in the next 30 days, higher than 44.1% of scored vulnerabilities.

Timeline

1. 18-06-2025
   PublishedVulnerability first disclosed.
2. 18-06-2025
   Last modifiedVulnerability information updated.

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 denial of service (DoS) condition in the Cisco AnyConnect service on an affected device. This vulnerability is due to variable initialization errors when an SSL VPN session is established. An attacker could exploit this vulnerability by sending a sequence of crafted HTTPS requests to an affected device. A successful exploit could allow the attacker to cause the Cisco AnyConnect VPN server to restart, resulting in the failure of all established SSL VPN sessions and forcing remote users to initiate a new VPN connection and re-authenticate. A sustained attack could prevent new SSL VPN connections from being established, effectively making the Cisco AnyConnect VPN service unavailable for all legitimate users.

• CWE-457Use of Uninitialized VariableThe code uses a variable that has not been initialized, leading to unpredictable or unintended results.