CVE-2023-20269Actively exploitedAdded to KEV 2023-09-13Critical severity, CVSS 9.1Known ransomware campaign use

Cisco Adaptive Security Appliance and Firepower Threat Defense Unauthorized Access Vulnerability

Cisco, Adaptive Security Appliance and Firepower Threat Defense

Description

Cisco Adaptive Security Appliance and Firepower Threat Defense contain an unauthorized access vulnerability that could allow an unauthenticated, remote attacker to conduct a brute force attack in an attempt to identify valid username and password combinations or establish a clientless SSL VPN session with an unauthorized user.

CVSS severity

Critical (9.1/10)

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

Sourced from NVD, reflects how severe this vulnerability is if exploited, not whether it has been. Every advisory on this page is already a CISA-confirmed active exploitation case regardless of its CVSS score.

EPSS, exploit probability

High

26.6%

estimated chance of real-world exploitation in the next 30 days, higher than 98.0% of every CVE FIRST.org scores

Refreshed 10/28/2026, via FIRST.org's EPSS model, not CVSS, this measures likelihood of exploitation, not how severe it would be.

Required action

Apply mitigations per vendor instructions for group-lock and vpn-simultaneous-logins or discontinue use of the product for unsupported devices.

CISA-recommended due date: 2023-10-04

CWE-288

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