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Vulnerabilities

Vulnerability · CVE-2025-34027

versa-networks concerto Time-of-check Time-of-use (TOCTOU) Race Condition

Published May 21, 2025 · catalog updated Feb 26, 2026 · Versa Concerto

Patch now

CVE-2025-34027 is in the CISA known-exploited catalog. Confirm Versa Concerto against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
Critical10.0
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
45.82%
Remediation
Remediation guidance
Affected products
vendor Versa Concerto 12.1.2 ≤12.2.0 · vendor Versa Networks Versa Concerto SD-WAN Orchestration Platform

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor Versa Concerto 12.1.2 ≤12.2.012.1.2 ≤12.2.0
  • vendor Versa Networks Versa Concerto SD-WAN Orchestration Platformversion unspecified

How to fix CVE-2025-34027

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2025-34027 is in the CISA known-exploited catalog. Confirm Versa Concerto against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with Versa Concerto 12.1.2 ≤12.2.0 12.1.2 ≤12.2.0. Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

What should an analyst verify?

No weakness class is stored. EPSS 45.82%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jul 21, 2025 · VulnCheck KEV

    Detected

    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 un

  2. Jul 21, 2025 · CISA KEV

    Known exploited

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

  3. Feb 26, 2026 · EUVD

    Updated

    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 un

Sources

  • CVE.orgVulnerability recordCVE-2025-34027

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-34027

    30-day exploitation probability 45.8%

    first.org
  • EUVDVulnerability recordEUVD-2025-16088

    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) w

    euvd.enisa.europa.eu
  • VulnCheck KEVConfirmed exploitationCVE-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) w

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.