What it is
CVE-2025-34027 is an unauthenticated Versa Concerto Authentication Bypass File Write Remote Code Execution. The Versa Concerto SD-WAN orchestration platform is vulnerable to an authentication bypass in the Traefik...
Vulnerability report
Exploited in the wild
High confidence
Not in CISA KEV
CVE-2025-34027
Versa Concerto Authentication Bypass File Write Remote Code Execution
Versa / Concerto · 12.1.2 to <= 12.2.0
- Severity
- CVSS 10.0 · Critical
- Confidence
- High
- Exploit status
- Exploited in the wild
- EPSS
- 37.0%
- First observed
- —
- Last observed
- —
Decision summary
What security teams need to know first
Direct answers before the deeper technical record.
Is it exploited?
Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is high.
Who is affected?
Versa / Concerto 12.1.2 to <= 12.2.0.
What should we do?
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
Overview
Versa Concerto Authentication Bypass File Write Remote Code Execution
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.
Vendor
Product
Affected
Status
Versa
Concerto
Through 12.2.0
Affected
- Published
- 21 May 2025
- Exploitation Reported
- 01 Aug 2025
- Attack vector
- Remote
- Complexity
- Low
- Privileges
- None
- User interaction
- None
Tags
nuclei_scanner
CVE References
- CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2025-34027
- Exploit — projectdiscovery.io projectdiscovery.io · Exploit https://projectdiscovery.io/blog/versa-concerto-authentication-bypass...
Exploitation evidence
Why KEV Intelligence marks this CVE as exploited
Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.
Exploited in the wild
The Shadowserver
Independent exploitation attestation added to the KEV Intelligence record.
Proof of concept available
Nuclei Templates
Public scanner or PoC coverage increases practical exploitability.
Known exploited vulnerability sources
Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| The Shadowserver First | 2025-08-01 00:00 UTC |
Detection
Operational artifacts and observed signals
Make the evidence actionable in scanner, SOC, and edge-control workflows.
Observed signals
- Request targets
- 0
- User-Agents
- 0
Raw values available in Pro and Enterprise.
Scanner coverage
Nuclei template detected 01 Jun 2026.
View Nuclei template (opens in new tab)Virtual patch status
No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.
Learn about virtual patches →Scanner Artifacts
Scanner and exploit-framework references linked to this CVE.
| Scanner | Reference | Detected |
|---|---|---|
| Nuclei | https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2025/CVE-2025-34027.yaml | 01 Jun 2026 |
Risk and context
Severity, weaknesses, and research context
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
EPSS
37.0%
Potential Proof of Concepts
These PoCs are unverified and could contain malware. Use at your own risk.
Versa Concerto API Path Based - Authentication Bypass
nuclei · Created Unknown
Timeline
From disclosure to observed exploitation
-
Public PoC available
Public proof-of-concept code published
-
Nuclei template available
Scanner coverage available
-
Added to KEV Intelligence KEV Feed
High-confidence, third-party attested exploitation
-
CVE published
Vulnerability disclosed publicly
-
CVE ID reserved
Identifier reserved by the CNA
Pro API
Automate this intelligence
Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
- Evidence confidence and provenance
- First-party sensor telemetry
- PoC and scanner references
- Affected versions and enrichment
- Automation-ready JSON delivery
GET /api/v2/pro/kevs/CVE-2025-34027
Free JSON includes basic KEV fields{
"cve_id": "CVE-2025-34027",
"confidence": "High",
"cvss_score": 10.0,
"cvss_estimated": false,
"epss_score": 0.3698,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "attempts": 0, "sensors": 0 }
}Early warning alerts
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