CVE-2026-11348: Cryptographic Signature Bypass in HAVELSAN Liman MYS

Technical summary

CVE-2026-11348 is an improper cryptographic signature verification vulnerability (CWE-347) in Liman MYS. The flaw permits attackers to bypass signature validation mechanisms, enabling them to fabricate or alter data while making it appear to originate from a trusted source. The CVSS 3.1 vector (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H) indicates network exploitability with high complexity, affecting confidentiality, integrity, and availability. No user interaction is required.

Business impact

Exploitation could enable unauthorized command injection, system compromise, or data manipulation within Liman MYS deployments. If Liman MYS is used for critical operational technology, defense systems, or administrative control, an attacker could issue fraudulent directives that appear authorized, leading to service disruption, data theft, or loss of system integrity. Recovery requires confirming the legitimacy of transactions or commands executed during the exposure window.

Affected systems

HAVELSAN Liman MYS versions prior to Master.1107 are affected. Organizations running earlier builds should prioritize asset discovery to identify all instances and determine criticality based on deployment context and data sensitivity.

Exploitability

The vulnerability is network-accessible and requires no credentials or user interaction, making it remotely exploitable. However, the attack complexity is rated high, suggesting that successful exploitation may depend on specific timing, network conditions, or knowledge of the target's cryptographic implementation. It is not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog, but the lack of KEV status does not indicate unavailability of working exploits in private threat actor arsenals.

Remediation

Upgrade Liman MYS to release Master.1107 or later. Before patching, consider network segmentation to limit access to Liman MYS instances, restrict administrative interfaces, and monitor for suspicious cryptographic validation failures or unexpected command origination patterns.

Patch guidance

Apply the upgrade to Liman MYS Master.1107 or subsequent releases as soon as possible. Verify the upgrade in a non-production environment first to confirm compatibility with existing deployments. Obtain official release notes from HAVELSAN to confirm the patch addresses CWE-347 signature verification. After patching, perform signature validation testing if your environment includes custom integrations or API consumers.

Detection guidance

Monitor logs for failed signature verifications, unexpected source IPs issuing commands, or repeated authentication attempts using forged credentials. If Liman MYS provides audit trails, examine for transactions originating from unusual sources or with mismatched signature timestamps. Network-based detection should focus on abnormal traffic patterns to administrative interfaces or command channels. Consider deploying integrity monitoring to detect unauthorized data modifications.

Why prioritize this

This vulnerability merits urgent attention because it directly undermines trust in data origin—a fundamental security property. The CVSS 8.1 HIGH rating combined with remote exploitability and high impact on confidentiality, integrity, and availability justifies prioritization ahead of lower-severity issues. The lack of user interaction lowers the barrier to exploitation. Organizations should treat this as a critical control point if Liman MYS underpins operational or administrative workflows.

Risk score, explained

CVSS 3.1 score of 8.1 (HIGH) reflects network accessibility, no authentication requirement, and comprehensive impact across confidentiality, integrity, and availability. The high attack complexity moderates the score but does not change the severity tier. The absence of KEV designation does not reduce exploitability risk; it reflects lack of confirmed active exploitation reports at publication time, not difficulty of weaponization.

Frequently asked questions