CVE-2026-11340 — Missing Authorization in HAVELSAN Liman MYS

A critical missing authorization vulnerability, identified as CVE-2026-11340, has been disclosed in HAVELSAN Inc.'s Liman MYS, affecting all versions before release.Master.1107. This flaw stems from the application's failure to properly constrain access to certain functionalities by Access Control Lists (ACLs). This means that a low-privileged authenticated attacker could potentially access and manipulate features or data that should be restricted to higher-privileged users. With a CVSS v3.1 base score of 8.3 (High), this vulnerability poses a significant risk of high impact to data integrity and system availability, and low impact to confidentiality, if exploited. Defenders should prioritize patching this vulnerability to prevent unauthorized access and potential system compromise.

Attack Chain

1. An attacker, possessing valid low-privileged credentials, identifies a vulnerable HAVELSAN Liman MYS instance (versions prior to release.Master.1107).
2. The attacker authenticates to the Liman MYS web interface using their legitimate low-privileged account.
3. The attacker then crafts a request or navigates to a specific sensitive function or resource that should typically be restricted by ACLs to higher-privileged users.
4. Due to the missing authorization vulnerability (CVE-2026-11340), the Liman MYS application fails to adequately verify the attacker's authorization level for the requested resource or action.
5. The application incorrectly grants the low-privileged attacker access to the restricted functionality or data, bypassing intended security controls.
6. The attacker can then perform unauthorized actions, such as modifying critical system configurations, accessing sensitive information, or triggering disruptive operations.
7. This unauthorized access ultimately leads to high impact on the system's integrity (e.g., data tampering, unauthorized changes) and availability (e.g., service disruption), with a low impact on confidentiality.

Impact

The exploitation of CVE-2026-11340 can lead to severe consequences for organizations utilizing HAVELSAN Inc. Liman MYS. While specific victim counts are not available, successful exploitation by a low-privileged attacker could result in high impact to the integrity of the system and data, allowing for unauthorized modifications or deletions. Additionally, the availability of critical services could be severely affected, potentially leading to denial of service conditions. Confidentiality is also impacted, albeit at a lower level, as unauthorized data access might occur. Given Liman MYS's role, such compromise could disrupt operational management and expose sensitive internal configurations.

Recommendation

• Immediately apply the patch to update HAVELSAN Liman MYS to release.Master.1107 or a later secure version to remediate CVE-2026-11340.
• Enable comprehensive web application logging on your HAVELSAN Liman MYS instances to capture all HTTP requests, including request methods, URIs, user agents, and source IP addresses, to aid in detecting abnormal access patterns.
• Regularly audit Access Control Lists (ACLs) and authorization configurations within Liman MYS to ensure they align with the principle of least privilege and prevent similar authorization bypasses.