CVE-2025-34027: Versa-Networks Concerto

Critical severity, CVSS 9.0. EPSS: 45.2% chance of exploitation in the next 30 days.

The Versa Concerto SD-WAN orchestration platform is vulnerable to an authentication bypass in the Traefik reverse proxy configuration, allowing at attacker to access administrative endpoints. The Spack upload endpoint can be leveraged for a Time-of-Check to Time-of-Use (TOCTOU) write in combination with a race condition to achieve remote code execution via path loading manipulation, allowing an unauthenticated actor to achieve remote code execution (RCE).This issue is known to affect Concerto from 12.1.2 through 12.2.0. Additional versions may be vulnerable.

Affected products

• Versa-Networks Concerto: from 11.4.0, up to and including 12.1.1; version 12.1.2 only; version 12.2.1 only

Published 2025-05-21. Last modified 2026-08-25.