Critical CVSS 9.6

Overview

Arista NG Firewall User-Agent Cross-Site Scripting Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Arista NG Firewall. Minimal user interaction is required to exploit this vulnerability.

The specific flaw exists within the processing of the User-Agent HTTP header. The issue results from the lack of proper validation of user-supplied data, which can lead to the injection of an arbitrary script. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-24407.

Risk analysis

This vulnerability is rated 🔴 CRITICAL.

  • CVSS: 9.6 (CRITICAL)
  • Detected tags: rce, xss (tag impact: VERY HIGH)

Recommended actions:

  • Patch/upgrade immediately (remote code execution).
  • Reduce exposure (WAF/segmentation), minimize attack surface.
  • Apply context-aware output encoding.
  • Enable Content-Security-Policy and HttpOnly/SameSite cookies.

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