CVE-2025-34027 (GCVE-0-2025-34027)

Vulnerability from cvelistv5 – Published: 2025-05-21 21:58 – Updated: 2026-02-26 18:27
VLAI Shadowserver Previdian
Title
Versa Concerto Authentication Bypass File Write Remote Code Execution
Summary
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.
Severity
10 (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
SSVC
Exploitation: none Automatable: yes Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-05-28 03:56 UTC
CWE
  • CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition
Assigner
VulnCheck CNA under the mitre root
CNA scorecard B 84/100 over 7812 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Versa Concerto Affected: 12.1.2 , ≤ 12.2.0 (semver)
    cpe:2.3:a:versa:concerto:*:*:*:*:*:*:*:*
Create a notification for this product.
Credits
ProjectDiscovery Harsh Jaiswal Rahul Maini Parth Malhotra
Shadowserver
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: cca32a6d-e91f-4c6f-bb81-3f7a8044b420

Vulnerability ID: CVE-2025-34027

Status: Confirmed

Status Updated: 2026-11-04 00:00 UTC

Exploited: Yes

Characteristics
Severity: 0.0
Timestamps
First Seen: 2025-07-21
Asserted: 2025-07-21
Last Seen: 2026-11-04
Scope
Asset Exposure: ['internet-facing']
Notes: Affected: Versa / Versa Concerto | Class: device-management-platform | Severity: None (CVSS 0) | IoT: no | In CISA KEV: no | Honeypot connections on 2026-11-04: 3
Evidence

Type: Honeypot

Signal: In The Wild Attempts

Confidence: 70%

Source: shadowserver

Details
1D 1
Iot no
Feed Shadowserver Foundation honeypot/exploited-vulnerabilities
Type http-scan
Class device-management-platform
7D Avg 0
Vendor Versa
30D Avg 2
90D Avg 1
Product Versa Concerto
Cisa Kev no
Connections 3
Observation Date 2026-11-04
Vulnerability Class CVSS
Vulnerability Score 0
Vulnerability Severity None
References
Created: 2026-07-01 07:18 UTC | Updated: 2026-11-06 01:02 UTC
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: 7af594db-7bf5-43e1-8b9d-99d97562f142

Vulnerability ID: CVE-2025-34027

Status: Confirmed

Status Updated: 2025-08-01 00:00 UTC

Exploited: Yes

Timestamps
First Seen: 2025-08-01
Asserted: 2025-08-01
Scope
Notes: KEVIntel entry: Versa Concerto Authentication Bypass File Write Remote Code Execution | Affected: Versa / Concerto | CVSS: 10.0 (CRITICAL) | Used in malware: unknown | Not yet in CISA KEV: True
Evidence

Type: Public Report

Signal: Successful Exploitation

Confidence: 70%

Source: kevintel

Details
Feed KEVIntel (kevintel.com)
Title Versa Concerto Authentication Bypass File Write Remote Code Execution
Vendor Versa
Product Concerto
Added Date 2025-08-01T00:00:00.000Z
Cvss Score 10.0
Epss Score None
Cvss Severity CRITICAL
Epss Percentile None
Used In Malware unknown
Ahead Of Cisa Kev None
Not Yet In Cisa Kev True
References
Created: 2026-06-23 11:12 UTC | Updated: 2026-06-23 11:12 UTC
Show details on NVD website
To clipboard 

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                "vectorString": "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",
                "version": "4.0",
                "vulnAvailabilityImpact": "LOW",
                "vulnConfidentialityImpact": "HIGH",
                "vulnIntegrityImpact": "HIGH",
                "vulnerabilityResponseEffort": "NOT_DEFINED"
              },
              "format": "CVSS",
              "scenarios": [
                {
                  "lang": "en",
                  "value": "GENERAL"
                }
              ]
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-367",
                  "description": "CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2025-11-28T19:43:34.727Z",
            "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
            "shortName": "VulnCheck"
          },
          "references": [
            {
              "tags": [
                "exploit",
                "mitigation"
              ],
              "url": "https://projectdiscovery.io/blog/versa-concerto-authentication-bypass-rce"
            }
          ],
          "source": {
            "discovery": "UNKNOWN"
          },
          "title": "Versa Concerto Authentication Bypass File Write Remote Code Execution",
          "x_generator": {
            "engine": "vulncheck"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "assignerShortName": "VulnCheck",
        "cveId": "CVE-2025-34027",
        "datePublished": "2025-05-21T21:58:31.698Z",
        "dateReserved": "2025-04-15T19:15:22.545Z",
        "dateUpdated": "2026-02-26T18:27:59.207Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON
How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

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    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.