by Kastro
Paper/Archive/CVE-2025-34027

CVE-2025-34027

Versa Concerto — Versa Concerto Authentication Bypass File Write Remote Code Execution

EPSS 46%CVSS 10.0
critical.is priorityof 100
50
CVSS 10.0 (CNA)10.0 / 10 × 3030.0Not in CISA KEV+300.0EPSS percentile 98.8.988 × 2019.8No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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

ProductAffectedFixed inSource
Concerto12.1.2 – 12.2.0–CNA

Scores by source

VulnCheck (CNA)10.0CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L
NVD9.0CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

exploitprojectdiscovery.io/blog/versa-concerto-authentication-bypass-rce