CVE-2020-3578: Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software WebVPN Portal Access Rule Bypass Vulnerability

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-10-21 · updated 2026-08-11
Weakness: CWE-863

Description

A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass a configured access rule and access parts of the WebVPN portal that are supposed to be blocked. The vulnerability is due to insufficient validation of URLs when portal access rules are configured. An attacker could exploit this vulnerability by accessing certain URLs on the affected device.

Affected products

Cisco ASA Software: before 9.6.4.45; from 9.7 before 9.8.4.26; from 9.9 before 9.9.2.80; from 9.10 before 9.10.1.44; from 9.12 before 9.12.4.4; from 9.13 before 9.13.1.13 — fixed in 9.10.1.44, 9.12.4.4, 9.13.1.13, 9.14.1.19, 9.6.4.45, 9.8.4.26
Cisco Firepower Threat Defense: before 6.3.0.6; from 6.5.0 before 6.5.0.5; from 6.6.0 before 6.6.1 — fixed in 6.3.0.6, 6.5.0.5, 6.6.1
Cisco Firepower Threat Defense Software: from 6.4.0 before 6.4.0.10 — fixed in 6.4.0.10

How to fix

Upgrade to a fixed version: Cisco ASA Software 9.10.1.44, 9.12.4.4, 9.13.1.13, 9.14.1.19; Cisco Firepower Threat Defense 6.3.0.6, 6.5.0.5, 6.6.1; Cisco Firepower Threat Defense Software 6.4.0.10. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2020-3578 or the next vulnerability affects your stack