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10.0
CVSS
Critical

CVE-2025-34027

PUBLISHED

Versa Concerto Authentication Bypass File Write Remote Code Execution

Exploited in the wild Remote Low complexity No user interaction
Vendor
Versa
Product
Concerto
Published
May 21, 2025
EPSS
—

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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.

nuclei_scanner

Weaknesses (CWE)

  • CWE-367

    Time-of-check Time-of-use (TOCTOU) Race Condition

CVSS scores

CVSS v4.0 10.0 Critical

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L

Exploitation status

Exploited in the wild

Recorded 2025-08-01 00:00:00 UTC · The Shadowserver (via CIRCL)

References

Known exploited vulnerability sources

Catalogues that list this CVE as a known exploited vulnerability.

Source Added
The Shadowserver (via CIRCL) First 2025-08-01 00:00 UTC

Scanner integrations

Scanner Reference Detected
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2025/CVE-2025-34027.yaml Jun 01, 2026

Timeline

  • CVE ID Reserved

  • CVE Published to Public

  • Added to KEVIntel

  • Detected by Nuclei