Versa Concerto up to 12.2.0 Traefik Reverse Proxy Configuration race condition

Summaryinfo

A vulnerability, which was classified as critical, has been found in Versa Concerto up to 12.2.0. Affected by this vulnerability is an unknown functionality of the component Traefik Reverse Proxy Configuration Handler. The manipulation leads to race condition. This vulnerability is uniquely identified as CVE-2025-34027. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability was found in Versa Concerto up to 12.2.0 and classified as critical. This issue affects an unknown functionality of the component Traefik Reverse Proxy Configuration Handler. The manipulation with an unknown input leads to a race condition vulnerability. Using CWE to declare the problem leads to CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The weakness was disclosed by Parth Malhotra. It is possible to read the advisory at projectdiscovery.io. The identification of this vulnerability is CVE-2025-34027 since 04/15/2025. The exploitation is known to be difficult. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. The technical details are unknown and an exploit is not publicly available.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-16088). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

• Versa

Name

• Concerto

Version

• 12.0
• 12.1
• 12.2.0

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CPE 2.2info

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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