CVE-2025-20271 — HIGH (8.6)

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 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.

CVSS Score

8.6

HIGH

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

Related Weaknesses (CWE)

CWE-457

References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/ci

FAQ

What is CVE-2025-20271?

CVE-2025-20271 is a vulnerability with a CVSS score of 8.6 (HIGH). 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 ...

How severe is CVE-2025-20271?

CVE-2025-20271 has been rated HIGH with a CVSS base score of 8.6/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2025-20271?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.