CVE-2026-17070 Overview
CVE-2026-17070 is a Missing Authorization vulnerability [CWE-862] affecting HAVELSAN Inc. Liman MYS. The flaw allows authenticated users to access functionality that is not properly constrained by Access Control Lists (ACLs). Affected versions range from 2.2.3 up to, but not including, 2.3.1.
An attacker with low-privilege network access can invoke restricted functionality and compromise confidentiality, integrity, and availability of the system. The Turkish national cybersecurity authority published advisory TR-26-0741 tracking this issue.
Critical Impact
Authenticated attackers with minimal privileges can reach administrative or restricted functionality over the network, resulting in full compromise of data confidentiality, integrity, and availability within Liman MYS.
Affected Products
- HAVELSAN Liman MYS version 2.2.3
- HAVELSAN Liman MYS versions between 2.2.3 and 2.3.1
- HAVELSAN Liman MYS versions prior to 2.3.1
Discovery Timeline
- 2026-08-04 - CVE-2026-17070 published to the National Vulnerability Database
- 2026-08-04 - Last updated in NVD database
Technical Details for CVE-2026-17070
Vulnerability Analysis
Liman MYS fails to enforce authorization checks on specific application functionality. When a request reaches a protected feature, the application authenticates the caller but does not verify whether the caller has permission to invoke that action. This maps to Common Weakness Enumeration [CWE-862], Missing Authorization.
The vulnerability is exploitable over the network with low attack complexity. It requires low-privilege credentials and no user interaction, which broadens the pool of potential attackers to any account holder within reach of the management interface. Successful exploitation impacts confidentiality, integrity, and availability at a high level.
Root Cause
The root cause is an incomplete access control layer. The affected endpoints or workflows in Liman MYS rely on authentication as a proxy for authorization. Function-level checks that verify role, group, or ACL membership are either absent or incorrectly applied on the sensitive code paths. Any authenticated session can therefore reach functionality that should be restricted to privileged administrators.
Attack Vector
An attacker obtains or is issued a low-privilege account on the Liman MYS instance. The attacker then issues HTTP requests directly to endpoints that expose privileged operations. Because the server does not enforce ACL checks on these endpoints, the requests are processed as if invoked by an authorized user. This can lead to modification of managed systems, disclosure of sensitive server data, and disruption of managed services.
No verified exploit code has been published. Refer to the Siber Güvenlik Notification TR-26-0741 for vendor-supplied technical details.
Detection Methods for CVE-2026-17070
Indicators of Compromise
- Requests to Liman MYS administrative or privileged endpoints originating from low-privilege user sessions or service accounts.
- Unexpected configuration changes, user creations, or extension installations performed by non-administrator accounts.
- HTTP 200 responses on privileged API paths where the session role does not match the operation.
Detection Strategies
- Correlate authentication logs with authorization decisions to identify sessions invoking privileged actions without matching role assignments.
- Baseline normal API usage per role in Liman MYS and alert on deviations, especially privileged operations performed by standard users.
- Review web server and application logs for direct calls to admin routes lacking the expected referer or workflow context.
Monitoring Recommendations
- Enable verbose audit logging in Liman MYS and forward events to a centralized log platform for retention and correlation.
- Monitor for lateral movement following any suspicious privileged action, including new SSH key uploads or extension deployments on managed hosts.
- Alert on any modification to user, role, or ACL objects that is not attributable to an authorized administrator change ticket.
How to Mitigate CVE-2026-17070
Immediate Actions Required
- Upgrade Liman MYS to version 2.3.1 or later on all instances running versions between 2.2.3 and 2.3.1.
- Restrict network access to the Liman MYS management interface to trusted administrative networks and jump hosts only.
- Audit all Liman MYS accounts and revoke unused or dormant low-privilege credentials that could be leveraged by an attacker.
- Review recent audit logs for evidence of unauthorized use of privileged functionality and treat confirmed activity as an incident.
Patch Information
HAVELSAN addresses the issue in Liman MYS 2.3.1. Upgrade all affected deployments from the vulnerable range (>= 2.2.3, < 2.3.1) to the patched release. Consult the Siber Güvenlik Notification TR-26-0741 for the official remediation guidance.
Workarounds
- Place Liman MYS behind a reverse proxy or VPN that enforces additional authentication and IP allow-listing until patching is complete.
- Reduce the number of authenticated users on the platform to the minimum required for operations while remediation is in progress.
- Enforce multi-factor authentication for all Liman MYS accounts to raise the cost of credential misuse.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
