CVE-2026-25623: Arista NGFW Admin Command Injection Vulnerability

Technical summary

CVE-2026-25623 is an input validation flaw (CWE-78: Improper Neutralization of Special Elements used in an OS Command) residing in Arista NGFW's browser management pipeline. The vulnerability permits authenticated admin users to craft specially-formed requests that escape input sanitization, leading to OS command injection with system-level privileges. The attack vector is network-based with no user interaction required beyond the initial malicious request submission.

Business impact

This vulnerability poses a significant insider risk or post-compromise threat. An administrator account—whether legitimately held or compromised—can escalate from web UI access to full system command execution. This enables attackers to deploy backdoors, exfiltrate sensitive traffic policies, modify firewall rules to enable lateral movement, or disable security controls entirely. For organizations relying on Arista NGFW as a perimeter defense, command-level compromise represents critical loss of control.

Affected systems

Arista Next Generation Firewall (NGFW) is affected. Specific product versions are not disclosed in the vulnerability record; consult Arista's security advisory to identify exact affected releases and any version boundaries.

Exploitability

Exploitation requires valid administrator credentials and network access to the firewall's web management interface. While the bar for unauthenticated access is high, the lack of additional complexity (AC:L) and the high privilege requirement (PR:H) reflect a scenario where a compromised or malicious admin account poses immediate system compromise risk. Public exploits are not tracked in CISA's Known Exploited Vulnerabilities (KEV) catalog.

Remediation

Apply the security patch released by Arista for this CVE. Verify the patched version against Arista's official advisory. Additionally, implement network segmentation to restrict admin console access to trusted management networks, enforce multi-factor authentication for administrative logins, and maintain audit logs of all management interface activity to detect anomalous commands.

Patch guidance

Obtain the patched version from Arista's security advisory or update portal. Test the patch in a non-production environment before deployment to firewall production instances. Coordinate patching during a maintenance window to minimize management interface downtime. Verify successful patching by checking the firewall's firmware/software version post-update.

Detection guidance

Monitor firewall management logs for unusual command patterns or system-level operations initiated via the web console. Look for shell metacharacters, pipe symbols, or command chaining in admin request logs. Implement intrusion detection signatures for OS command injection attempts if available from your IDS vendor. Monitor process execution on the firewall appliance for unexpected child processes spawned by management services. Alert on any outbound connections or file writes initiated by administrative sessions outside normal maintenance windows.

Why prioritize this

Although rated MEDIUM severity (CVSS 6.0), this vulnerability should be prioritized above its score suggests because it affects a critical security appliance and enables complete system compromise by a privileged insider. Organizations should treat it as HIGH priority operationally, especially if their Arista NGFW is internet-facing or manages sensitive traffic. The requirement for admin credentials mitigates widespread automated exploitation, but the impact of successful abuse is severe.

Risk score, explained

CVSS 3.1 score of 6.0 reflects: network accessibility (AV:N), low attack complexity (AC:L), high privilege requirement (PR:H), no user interaction (UI:N), unchanged scope (S:U), high confidentiality impact via terminal access (C:H), limited integrity impact (I:L), and limited availability impact (A:L). The score appropriately captures a privileged-user threat with severe access implications but lower likelihood of mass exploitation.

Frequently asked questions