CVE-2025-34027

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.

CVSS v4.0

10.0 CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1

9.0 CRITICALCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS

45.22% chance of exploitation in the next 30 days, 99th percentile

Nuclei

critical · CWE-367

Published

2025-05-21

Updated

2026-02-26

Proof-of-concept exploits (1)

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

Nuclei templates (1)

• projectdiscovery/nuclei-templates/blob/main/http/cves/2025/CVE-2025-34027.yaml

References

• CVE Record
• NVD entry

Related

• CVE-2025-34026
• CVE-2025-34028
• CVE-2025-34025
• CVE-2025-34029
• CVE-2025-34024
• CVE-2025-3403