CVE-2026-25621: Arista NGFW 17.4.0 Reports Input Validation Vulnerability

Technical summary

CVE-2026-25621 is an OS command injection vulnerability (CWE-78) in the Arista NGFW Reports application infrastructure affecting only version 17.4.0. The vulnerability stems from insufficient input validation on user-supplied parameters. The attack vector is network-based and requires high privileges (PR:H), meaning the attacker must already possess administrative or equivalent credentials. No user interaction is required for exploitation once the attacker is authenticated. The CVSS 3.1 score of 6.0 (MEDIUM) reflects high confidentiality impact, low integrity impact, and low availability impact with no scope expansion.

Business impact

Organizations running Arista NGFW 17.4.0 face a risk of unauthorized information disclosure from the Reports application. An insider or compromised high-privileged account could exfiltrate sensitive network intelligence, policy configurations, or audit logs. The limited integrity and availability impact suggests the attack does not easily lead to widespread system corruption or denial of service, but the confidentiality risk warrants prompt attention in environments where the Reports application processes or stores classified data.

Affected systems

Only Arista Edge Threat Management NGFW version 17.4.0 is vulnerable. Organizations running earlier releases or later patched versions are not exposed. If you maintain an inventory of Arista NGFW appliances, filter for any instances explicitly reporting version 17.4.0 in management dashboards or via API queries.

Exploitability

Exploitation requires an authenticated attacker with high-level administrative privileges on the NGFW. This significantly reduces the attack surface compared to unauthenticated exploits. Network accessibility is required, but the barrier to exploitation is the attacker's pre-existing privileged access—making this a concern for insider threats or lateral movement following a breach of adjacent systems. No public exploit code or KEV listing elevates the urgency, but the attack is straightforward once conditions are met.

Remediation

Upgrade Arista NGFW to a version released after 17.4.0. Consult the Arista security advisory or release notes to confirm that the patch addresses CVE-2026-25621. In environments where immediate patching is delayed, implement strict role-based access controls to limit Reports application access to only essential personnel, and monitor Reports API activity for anomalous query patterns or command-like payloads.

Patch guidance

Verify the next available stable release of Arista NGFW after version 17.4.0 against the official Arista security advisory to confirm the fix is included. Plan a maintenance window that accounts for Reports application downtime, and test the upgrade in a pre-production environment with representative Reports workloads. Once patched, re-baseline your Reports application configuration to ensure no malicious changes were introduced before the upgrade was applied.

Detection guidance

Monitor for abnormal activity in the Reports application, particularly failed input validation errors, unexpected command execution attempts, or queries with shell metacharacters (|, ;, &, `, $). Enable detailed logging on the Reports API endpoint and correlate with authentication logs to identify if high-privileged accounts are generating unusual query patterns. Search for payloads containing OS command sequences in application logs. Network intrusion detection systems should flag suspicious payload patterns targeting the Reports application interface.

Why prioritize this

Although the CVSS score is MEDIUM and exploitation requires high privileges, the confidentiality impact justifies timely remediation. The vulnerability is isolated to a single version, making the scope of affected deployments easier to define. Organizations should prioritize patching based on whether their Arista NGFW hosts Reports data classified as sensitive or confidential. This is not an emergency patch, but should not be deferred indefinitely.

Risk score, explained

The score of 6.0 reflects a balanced risk profile: high-impact data exposure (confidentiality) offset by a high privilege barrier (PR:H) and limited system-wide damage (low integrity and availability impact). The network vector and lack of user interaction eligibility keep the baseline from dropping further, but the privilege requirement prevents a higher score. For organizations where the Reports application is not internet-facing and access is tightly controlled, actual risk may be lower than the numeric score suggests.

Frequently asked questions