# CVE-2026-20064: Cisco Secure Firewall Threat Defense authenticated DoS via CLI input validation

Source: https://junglewise.ai/threats/cve-2026-20064-cisco-secure-firewall-threat-defense-authenticated-dos-via-cli  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-03-04. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-20064 · Severity: medium · CVSS 6.5 · Published 2026-03-04

Cisco Secure Firewall Threat Defense (FTD) is a network security appliance that protects enterprise networks by inspecting and blocking malicious traffic. A vulnerability in its command-line interface (CLI) allows an authenticated user with low-level privileges to crash the device by submitting specially crafted commands, causing a temporary service outage and preventing network traffic inspection until the device restarts.

Technologies: [Cisco Secure Firewall Threat Defense](https://junglewise.ai/threats/technologies/firepower-threat-defense). Vendors: [Cisco](https://junglewise.ai/threats/vendors/cisco).

## Quick answers

**Is CVE-2026-20064 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-20064 being exploited in the wild.

**How severe is CVE-2026-20064?** Medium severity, with a CVSS score of 6.5, published 4 March 2026.

**Which products and versions are affected?** Cisco Secure Firewall Threat Defense.

**Is there a fix for CVE-2026-20064?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-20064 attacked?** It is attacked with local access, in a network appliance.

**Am I affected by CVE-2026-20064?** Check whether you run Cisco Secure Firewall Threat Defense. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

CVE-2026-20064 is an authenticated denial-of-service vulnerability in Cisco Secure FTD Software's CLI feature, caused by insufficient input validation of user-supplied command arguments (CWE-88). An attacker with valid low-privileged local authentication can exploit this by submitting crafted input to a specific CLI command, triggering an unexpected device reload. The attack requires local access and valid credentials but no user interaction or elevated privileges. Cisco has released software updates to address this vulnerability; no workarounds are available.

## Affected products

- Cisco Secure Firewall Threat Defense

## Timeline

- 2026-03-04: disclosed

## References

- [https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-cmd-inj-mTzGZexf](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-cmd-inj-mTzGZexf)

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