CVE intelligence and bounded remediation

CVE-2026-20100 — Cisco Adaptive Security Appliance Software security vulnerability

High CVSS 7.7

A vulnerability in the LUA interperter of the Remote Access SSL VPN feature of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker with a valid VPN connection to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This does not affect the management or MUS interfaces. This vulnerability is due to trusting user input without validation in the LUA interprerter. An attacker could exploit this vulnerability by sending crafted HTTP packets to the Remote Access SSL VPN server. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

Severity
High
CVSS
7.7 (3.1)
Published
2026-03-04
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-120

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 222 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Buffer bounds, memory safety, and memory corruption

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Identify affected native-code versions, build flags, architectures, parsers, codecs, drivers, and input paths in all shipped artifacts.
  • Determine whether untrusted data reaches the affected routine and the process privilege, sandbox, and network exposure.
  • Confirm statically linked, vendored, firmware, and platform-provided copies, not only package-manager records.

Remediate safely

  • Apply the maintained upstream correction or replace the affected component, then rebuild every dependent artifact from clean inputs.
  • Adopt bounds-checked interfaces, validated sizes and integer conversions, clear ownership, and memory-safe components where practical.
  • Enable supported compiler and runtime hardening and add sanitized tests and fuzz regression seeds derived from non-weaponized fixtures.

Authoritative sources

Complete CVE record and remediation plan

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