What’s Vulnerable › Vulnerabilities

CVE-2025-34027: Versa Concerto Authentication Bypass File Write Remote Code Execution

• Severity: critical (CVSS 9.0 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 46.1% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2025-05-21 · updated 2026-08-25
• Weakness: CWE-367

Description

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 Concerto: from 11.4.0 through 12.1.1; 12.1.2, 12.2.1

References

• https://projectdiscovery.io/blog/versa-concerto-authentication-bypass-rce
• https://projectdiscovery.io/blog/versa-concerto-authentication-bypass-rce

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