CVE-2023-20269: in the CISA KEV catalogue

Cisco Adaptive Security Appliance and Firepower Threat Defense Unauthorized Access Vulnerability. CISA added CVE-2023-20269 to the Known Exploited Vulnerabilities catalogue on 2023-09-13 with a default due date of 2023-10-04. Known ransomware campaign use: Known. Forensic triage flag: No.

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. (CISA description)

Vendor / product

Cisco Adaptive Security Appliance and Firepower Threat Defense

CWE

CWE-288

CISA required action

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

EPSS

27%, percentile 98 (scored 2026-11-03)

EPSS puts about 27 in 100 odds (27%) on exploitation activity being observed in the next 30 days. Its score is higher than or equal to that of 98% of scored CVEs. This is a model estimate about exploitation anywhere, not about your environment.

Your own deadline under CISA BOD 26-04 depends on exposure, automatability and technical impact: work it out with the BOD 26-04 calculator.