CVE-2026-25621: Arista NG Firewall Input Validation Flaw

CVE-2026-25621 Overview

CVE-2026-25621 is a command injection vulnerability [CWE-78] in the Reports application infrastructure of Arista Edge Threat Management — Arista Next Generation Firewall (NGFW). The flaw stems from insecure input validation in the Reports component. The issue affects only version 17.4.0 of the product. Earlier software releases are not exposed. An authenticated attacker with high privileges can exploit the weakness over the network to compromise the confidentiality of the firewall and influence integrity and availability of adjacent components.

Critical Impact
Authenticated network attackers can inject operating system commands into the Reports application of Arista NGFW 17.4.0, exposing sensitive firewall data and impacting connected systems.

Affected Products

Arista Edge Threat Management — Arista Next Generation Firewall (NGFW) version 17.4.0
Reports application infrastructure component within NGFW 17.4.0
Earlier NGFW releases prior to 17.4.0 are not affected

Discovery Timeline

2026-06-05 - CVE-2026-25621 published to NVD
2026-06-08 - Last updated in NVD database

Technical Details for CVE-2026-25621

Vulnerability Analysis

The vulnerability resides in the Reports application infrastructure of Arista NGFW. The component fails to properly validate or sanitize input before incorporating it into operating system command execution. This pattern matches [CWE-78], OS Command Injection. An attacker who is authenticated to the management interface can craft input that breaks out of the intended command context. The injected payload executes within the privilege context of the Reports service. Because the Reports application has access to firewall telemetry, log data, and configuration metadata, confidentiality impact is high. The attack vector is network-based, complexity is low, and no user interaction is required.

Root Cause

The Reports application accepts user-controlled input and passes it to a downstream system command without rigorous sanitization or use of safe parameterized APIs. Standard secure coding practice requires input allowlisting, argument arrays instead of shell strings, and rejection of shell metacharacters. The absence of these controls in NGFW 17.4.0 introduced the regression. Earlier versions did not contain the affected code path.

Attack Vector

An attacker must already hold high-privilege credentials on the NGFW management plane. From there, the attacker submits a malicious request to the Reports application over the network. The crafted input embeds shell metacharacters or command separators that the backend executes on the host operating system. Successful exploitation yields arbitrary command execution within the Reports service context and can affect adjacent system components.

No verified public exploit code is available. Refer to the Arista Security Advisory #0133 for vendor technical details.

Detection Methods for CVE-2026-25621

Indicators of Compromise

Unexpected child processes spawned by the Reports application service on the NGFW host, particularly shell interpreters such as /bin/sh or /bin/bash.
Reports application log entries containing shell metacharacters such as ;, |, `, $(, or && in user-supplied parameters.
Outbound network connections originating from the Reports service to unfamiliar destinations.
Unscheduled modifications to files in directories writable by the Reports service account.

Detection Strategies

Review authenticated administrator session logs on NGFW 17.4.0 for anomalous activity targeting the Reports application endpoints.
Correlate Reports application request payloads with subsequent process execution events on the underlying operating system.
Apply signature-based inspection for known OS command injection patterns in HTTP requests to Reports application URIs.
Monitor for privilege escalation attempts or lateral movement following authenticated administrative sessions.

Monitoring Recommendations

Forward NGFW administrative and Reports application logs to a centralized log management or SIEM platform for retention and analysis.
Alert on any process execution chain that originates from the Reports application service and invokes a shell.
Track authentication events for high-privilege NGFW administrator accounts and flag access from atypical source addresses.
Establish a behavioral baseline for outbound traffic from the NGFW management plane and alert on deviations.

How to Mitigate CVE-2026-25621

Immediate Actions Required

Identify all NGFW deployments running version 17.4.0 and prioritize them for remediation.
Apply the fix referenced in the Arista Security Advisory #0133 as soon as it is available.
Restrict access to the NGFW management interface to a small set of trusted administrative networks.
Rotate credentials for any high-privilege administrator accounts that could have accessed the Reports application.

Patch Information

Arista has published Security Advisory #0133 describing this issue. Consult the advisory for the fixed software release and upgrade instructions. Because only version 17.4.0 is affected, downgrading to a prior unaffected release or upgrading to the vendor-supplied fixed build remediates the vulnerability.

Workarounds

Limit network reachability to the Reports application and the NGFW management plane using access control lists or a dedicated management VLAN.
Enforce multi-factor authentication for all administrative accounts to reduce the risk of credential compromise leading to exploitation.
Apply the principle of least privilege by removing unused high-privilege administrator accounts on the appliance.
Audit administrative activity on the Reports application and disable the feature for accounts that do not require it.

bash

# Configuration example: restrict management plane access
# Replace 10.10.0.0/24 with your trusted administrative subnet
iptables -A INPUT -p tcp --dport 443 -s 10.10.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP