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Mallory
Medium

Authenticated command injection in Cisco FXOS CLI for Cisco Secure Firewall ASA/FTD

IdentifiersCVE-2026-20016CWE-78

A vulnerability in the Cisco FXOS Software CLI feature for Cisco Secure Firewall ASA Software and Cisco Secure Firewall Threat Defense (FTD) Software allows an authenticated local attacker with valid administrative credentials to execute arbitrary commands on the underlying operating system with root-level privileges. The issue is caused by insufficient input validation of user-supplied command arguments; an attacker can submit crafted input to specific CLI commands to trigger command execution in the underlying OS context.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows arbitrary command execution on the underlying operating system with root-level privileges, resulting in full compromise of the affected device (e.g., complete loss of confidentiality/integrity/availability of the firewall/FTD system and its configuration and traffic-handling functions).

Mitigation

If you can’t patch tonight, do this now.

Restrict and monitor administrative access to affected devices (limit who can access the local CLI, enforce least privilege, and use strong administrative authentication controls). Because exploitation requires valid administrative credentials, reducing exposure of administrative interfaces and tightening admin access paths reduces risk until patches are applied.

Remediation

Patch, then assume compromise.

Apply Cisco-provided software updates that address CVE-2026-20016 for affected Cisco Secure Firewall ASA and FTD deployments using the FXOS CLI feature, per the corresponding Cisco Security Advisory.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Cisco SystemsAdaptive Security Appliance Softwareoperating_system
Cisco SystemsFirepower Threat Defense Softwareapplication
Cisco SystemsSecure Firewall Asa Softwareapplication
Cisco SystemsSecure Ftd Softwareapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity2

Community discussion across Reddit, Mastodon, and other social sources.