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critical·Product Based Web Vulnerabilities·Updated May 22, 2025

CVE-2025-34027 Scanner

Targets the URL decoding mechanism in Versa Concerto's API endpoints, allowing attackers to bypass authentication and access restricted functions without valid credentials.

Est. Time~10 seconds
Scan TypeSingle Scan
Targetsdomain, subdomain, ipv4
CostFree
3.1k
Times Used
continuous scan runs
5.5k
Continuously Checked
assets under CS
0
Vulnerabilities Found
confirmed findings
References
CVECVE-2025-34027
10.0
CVSScritical
Exploitable remotely over the internet · no authentication required.

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.

Attack Vector
Network
Privileges Req.
None
User Interaction
None
Affected
Concertoby Versa
12.1.2
Updated Aug 22, 2026View on NVD →
Detail

Versa Concerto is a comprehensive software deployed widely in enterprise environments for network management and security orchestration. Used primarily by IT departments, its purpose is to centralize control and monitoring of various network security protocols. The software facilitates the efficient handling of network resource allocation and security policy enforcement. Administrators utilize this platform to streamline operations and improve operational security. Its API capabilities allow for enhanced automation and integration within other enterprise systems, making it a critical tool for modern network infrastructures.

The Authentication Bypass vulnerability in Versa Concerto allows attackers to access restricted areas of the application without proper authorization. This flaw stems from inconsistencies in URL decoding, which can be exploited to bypass standard authentication mechanisms. Attackers can manipulate the URL path to gain unauthorized access to API endpoints, potentially compromising sensitive data. The vulnerability arises due to improper handling of encoded characters in the URL, leading to a mismatch between the decoded path and the expected authentication checks.

Specifically, the vulnerability affects the API endpoint used for user authentication and session management. By crafting a URL with double-encoded characters or using alternative encoding schemes, an attacker can trick the server into processing requests as if they came from an authenticated session. The parameter targeted is the path component of the HTTP request, where the server fails to normalize the URL before applying access controls. This allows the attacker to bypass the authentication middleware and directly invoke protected functions.

If exploited, this vulnerability can lead to complete compromise of the Versa Concerto instance. An attacker could gain administrative access, modify network configurations, exfiltrate sensitive data, or disrupt network operations. Given the critical role of Versa Concerto in enterprise networks, the impact could be severe, including data breaches, service outages, and compliance violations. The high CVSS score of 9.0 reflects the ease of exploitation and the potential for widespread damage.

Solution Advice
  • Update Versa Concerto to the latest patched version that addresses CVE-2025-34027.
  • Implement strict URL normalization and decoding routines to prevent encoding-based bypasses.
  • Apply additional authentication checks at all API endpoints, including those not requiring authentication.
  • Use a web application firewall (WAF) to detect and block malicious URL patterns.
  • Monitor access logs for unusual URL encoding patterns or repeated failed authentication attempts.
  • Conduct regular security audits and penetration testing focusing on authentication mechanisms.
  • Educate administrators on secure API configuration and the risks of URL manipulation.
  • Enforce least privilege access controls to limit the impact of a potential bypass.

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