Authorization Bypass in HAVELSAN Liman MYS

HAVELSAN Liman MYS, a centralized system management platform, contains a missing authorization vulnerability (CVE-2026-17070) affecting versions 2.2.3 through 2.3.0. The vulnerability originates from a failure to properly constrain access to administrative or sensitive functionality via Access Control Lists (ACLs). This allows an authenticated attacker with low-level privileges to bypass intended permission boundaries and execute operations normally reserved for higher-privileged roles. Given the platform's role in system management, this authorization flaw could lead to a full compromise of managed assets if an attacker performs unauthorized system configurations or service management tasks. Defenders should prioritize updating to version 2.3.1 or later to remediate this flaw.

Attack Chain

1. An attacker gains low-privileged access to the Liman MYS web interface via standard credentials.
2. The attacker navigates to the application and identifies functional endpoints or API routes that do not enforce server-side ACL checks.
3. The attacker crafts HTTP requests targeting these restricted endpoints (e.g., system configuration modules, user management, or service control interfaces).
4. The application processes the request without validating if the authenticated user possesses the required authorization level.
5. The attacker successfully executes the unauthorized administrative function, potentially escalating privileges or modifying system state.
6. The attacker leverages the gained administrative access to perform further malicious actions, such as deploying persistent backdoors, disabling security services, or exfiltrating sensitive system logs.

Impact

Successful exploitation of CVE-2026-17070 allows authenticated attackers to bypass security constraints and perform unauthorized administrative actions within the Liman MYS environment. This can result in complete loss of confidentiality, integrity, and availability of managed systems connected to the platform. The vulnerability carries a high CVSS 3.1 base score of 8.8.

Recommendation

Prioritize the upgrade of all HAVELSAN Liman MYS installations to version 2.3.1 or later. Since no specific payload signatures are available, detection should focus on anomalous access patterns to administrative modules within web server logs. Monitor for requests to sensitive URL paths that return 200 OK statuses from user accounts that do not belong to the administrative group. Ensure that access to the Liman MYS interface is strictly limited to authorized network segments to reduce the risk of exploitation by unauthorized parties.