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Vulnerability record · CVE-2026-20069 · published 4 March 2026

CVE-2026-20069: Cisco secure firewall threat defense http request smuggling vulnerability

Cisco · Secure Firewall Threat Defense

A vulnerability in the VPN web services component of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct browser-based attacks against users of an affected device. This vulnerability is due to improper validation of HTTP requests. An attacker could exploit this vulnerability by persuading a user to visit a website that is designed to pass malicious HTTP requests to a device that is running Cisco Secure Firewall ASA Software or Cisco Secure FTD Software and has web services endpoints supporting VPN features enabled. A successful exploit could allow the attacker to reflect malicious input from the affected device to the browser that is in use and conduct browser-based attacks, including cross-site scripting (XSS) attacks. The attacker is not able to directly impact the affected device.

4.3 CVSS 3.1 Medium EPSS 0.27% · top 82.3% CWE-444 · HTTP request smuggling
4.3CVSS 3.1 base score
0.27%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
1References
11 Aug 2026Last modified by NVD

Description

A vulnerability in the VPN web services component of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct browser-based attacks against users of an affected device. This vulnerability is due to improper validation of HTTP requests. An attacker could exploit this vulnerability by persuading a user to visit a website that is designed to pass malicious HTTP requests to a device that is running Cisco Secure Firewall ASA Software or Cisco Secure FTD Software and has web services endpoints supporting VPN features enabled. A successful exploit could allow the attacker to reflect malicious input from the affected device to the browser that is in use and conduct browser-based attacks, including cross-site scripting (XSS) attacks. The attacker is not able to directly impact the affected device.

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

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-desync-n5AVzEQw Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-20069), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.