CVE-2026-25623: Arista NG Firewall RCE Vulnerability

CVE-2026-25623 Overview

CVE-2026-25623 is a command injection vulnerability [CWE-78] in the browser management pipeline of Arista Edge Threat Management - Arista Next Generation Firewall (NGFW). The flaw stems from improper input validation, allowing authenticated administrators to execute arbitrary shell commands on the underlying operating system. Successful exploitation grants the attacker terminal script code processing execution permissions on the firewall appliance.

The vulnerability requires high privileges and authenticated administrator access, but it enables a privilege boundary crossing from the management interface to the host OS shell.

Critical Impact
Authenticated administrators can break out of the management interface and execute arbitrary OS-level commands on the NGFW appliance, undermining the trust boundary between the web UI and underlying host.

Affected Products

Arista Edge Threat Management - Arista Next Generation Firewall (NGFW)
arista:ng_firewall (all versions listed in Arista Security Advisory #0133)

Discovery Timeline

2026-06-05 - CVE-2026-25623 published to NVD
2026-06-08 - Last updated in NVD database

Technical Details for CVE-2026-25623

Vulnerability Analysis

The vulnerability resides in the browser-based management pipeline of the Arista NGFW. The management interface accepts input that is incorporated into shell command execution without sufficient validation or sanitization. This allows an attacker who has already authenticated as an administrator to inject shell metacharacters and execute arbitrary commands in the context of the script processor on the underlying system.

Classified under CWE-78 (Improper Neutralization of Special Elements used in an OS Command), the flaw represents a classic OS command injection pattern in a privileged management surface. The attack vector is network-based, so an attacker with administrative credentials can exploit the issue remotely without local console access.

The EPSS probability is 0.096%, indicating low predicted near-term exploitation activity. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog, and no public proof-of-concept has been published at the time of disclosure.

Root Cause

The root cause is missing or insufficient input sanitization on parameters processed by the management pipeline before being passed to a shell or script interpreter. User-supplied data flows into a command execution sink without escaping or argument-array invocation, enabling shell metacharacter interpretation.

Attack Vector

An authenticated administrator submits crafted input through the browser management interface. The input contains shell control characters or command separators. When the backend processes the request, the injected payload is concatenated into a command line and executed by the underlying script processor, yielding arbitrary command execution on the NGFW host.

No verified exploitation code is publicly available. Refer to the Arista Security Advisory #0133 for vendor-supplied technical context.

Detection Methods for CVE-2026-25623

Indicators of Compromise

Unexpected child processes spawned by the NGFW web management service or its script handlers.
Shell metacharacters such as ;, |, `, $(, or && appearing in management interface request parameters in web/audit logs.
New or modified files, cron entries, or SSH keys on the appliance that do not correspond to administrator activity.
Outbound network connections from the firewall management plane to unfamiliar hosts.

Detection Strategies

Inspect NGFW administrative audit logs for command-like input patterns submitted to management endpoints.
Alert on anomalous process trees originating from the web management service, particularly invocations of sh, bash, perl, or python.
Correlate administrator session activity with system-level command execution events to identify unexpected escalations to shell context.

Monitoring Recommendations

Forward NGFW management and system logs to a centralized log platform and retain them for incident review.
Monitor for changes to administrator account behavior, including off-hours logins and configuration changes immediately preceding shell activity.
Track outbound connections from the firewall itself, which should normally only initiate updates and telemetry to known vendor endpoints.

How to Mitigate CVE-2026-25623

Immediate Actions Required

Apply the fixed version listed in Arista Security Advisory #0133 as soon as the patched release is available for your deployment.
Restrict access to the NGFW browser management interface to a dedicated management network or jump host.
Rotate administrative credentials and review the administrator account inventory, removing unused or stale accounts.
Audit recent administrator activity for signs of command injection attempts or unexpected configuration changes.

Patch Information

Arista has published remediation guidance in Security Advisory #0133. Administrators should consult the advisory for the specific fixed software versions applicable to their NGFW deployment and follow the vendor's upgrade procedure.

Workarounds

Limit administrative access to the management UI using firewall rules, ACLs, or a bastion host until patching is complete.
Enforce multi-factor authentication for all NGFW administrator accounts to reduce the risk of credential-based exploitation.
Apply the principle of least privilege by minimizing the number of accounts with full administrative rights to the appliance.

bash

# Example: restrict NGFW management access to a single admin subnet
# (apply via upstream firewall or NGFW access policy)
allow  src 10.10.50.0/24  dst <ngfw-mgmt-ip>  proto tcp  dport 443
deny   src any            dst <ngfw-mgmt-ip>  proto tcp  dport 443