CVE-2025-34027: Versa Concerto Authentication Bypass File Write Remote Code Execution
- Is it exploited?
Reported, not confirmed by CISA. VulnCheck KEV lists it as exploited in the wild. CISA has not added it to its Known Exploited Vulnerabilities catalog as of .
VulnCheck KEV lists it since . It cites 206 public reports, the first from .
- How likely is exploitation in the next 30 days?
- 46.4%
Up from 46.1% on .
EPSS score, percentile 98.8 of all scored records. A probability estimated by FIRST, not a report of exploitation.
- How severe?
- 10.0 Critical
CVSS v4.0 base score, given by the CNA
- What should I do?
CISA has set no required action, because the vulnerability is not in KEV.
- Which versions are affected?
Affected
- 12.1.2 through 12.2.0
Source: CISA KEV 2026.10.29, as of ; VulnCheck KEV, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.
Description
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.
Source: CVE List, as of . About the data.
What to do
Advisories and patches
This summary is based on the CVE record as of . Check the vendor's advisory before you act: affected versions and fixes can change.
Affected products and versions
Versions by product, as listed in the CVE record (1 product)
| Status | Versions |
|---|---|
| Affected | 12.1.2 through 12.2.0 |
Versions not listed are: unknown.
Source: CVE List, as of . About the data.
Weakness
CWE-367, 2 CAPEC
- CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition
Attack patterns (CAPEC)
- CAPEC-38: Leveraging/Manipulating Configuration File Search Paths
- CAPEC-29: Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| CVE record last updated |
Known exploited Versa vulnerabilities
- CVE-2025-34026: Versa Concerto Improper Authentication Vulnerability
- CVE-2024-39717: Versa Director Dangerous File Type Upload Vulnerability