CVE intelligence and bounded remediation

CVE-2026-20070 — Cisco Adaptive Security Appliance Software security vulnerability

Medium CVSS 6.1

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 a cross-site scripting (XSS) attack against a browser that is accessing an affected device.  This vulnerability is due to improper validation of user-supplied input in HTTP requests. An attacker could exploit this vulnerability by persuading a user to follow a link to a malicious website that is designed to submit malicious input to the affected application. A successful exploit could allow the attacker to execute arbitrary HTML or script code in the browser in the context of the VPN web server.

Severity
Medium
CVSS
6.1 (3.1)
Published
2026-03-04
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-80

Affected products

  • cisco / adaptive_security_appliance_software / 9.12.1
  • cisco / adaptive_security_appliance_software / 9.12.1.2
  • cisco / adaptive_security_appliance_software / 9.12.1.3
  • cisco / adaptive_security_appliance_software / 9.12.2
  • cisco / adaptive_security_appliance_software / 9.12.2.1
  • cisco / adaptive_security_appliance_software / 9.12.2.4

Showing 6 representative product identities from 236 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Cross-site scripting and unsafe browser output

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Check exposure

  • Trace reflected, stored, and DOM-derived untrusted values into HTML, attributes, URLs, styles, scripts, and client-side template sinks.
  • Identify affected origins, authenticated user roles, sensitive browser capabilities, and where content is shared across tenants.
  • Review framework escaping, rich-text sanitization, legacy templates, and client-side rendering paths.

Remediate safely

  • Use context-aware framework output encoding and safe DOM APIs; keep untrusted data out of executable contexts.
  • Sanitize intentionally supported markup with a maintained allowlist policy and validate URLs and attributes separately.
  • Update affected rendering components and add tests for every output context using inert sentinel markup.

Authoritative sources

Complete CVE record and remediation plan

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