Versa-Networks Concerto
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.
What this means for your business
- It affects Versa-Networks Concerto. It matters if your company, or a supplier that handles your data, runs it.
- Code showing how to exploit it has been published, but real attacks have not been confirmed.
- An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 45% chance of attack attempts being seen in the next 30 days, ranking above 98% of all known flaws.
What to do
- 1Check whether your company or your suppliers run Versa-Networks Concerto, and which version. The affected versions are listed further down this page.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
Not sure if your company is exposed?
Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.
Scoring
- CVSS
- 9.0 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H- CVSS v4
- 10.0
- Weakness
- CWE-367
- Assigned by
- disclosure@vulncheck.com
Dates
- Published
- 2025-05-21
- Last modified
- 2026-08-25
- Sources
- NVD
Affected products
- Versa-Networks Concerto11.4.0 - 12.1.1, 12.1.2, 12.2.1
As listed in the NVD configuration data. Not a statement about your estate.