CVE-2026-11348 Overview
CVE-2026-11348 is an improper verification of cryptographic signature vulnerability [CWE-347] affecting HAVELSAN Liman MYS. The flaw allows attackers to fake the source of data by bypassing signature validation controls. Successful exploitation compromises the integrity of trusted data channels and enables attackers to impersonate legitimate sources over the network.
The issue affects Liman MYS releases prior to Master.1107. The vulnerability is exploitable over the network without authentication or user interaction, though attack complexity is rated high due to preconditions required for successful signature spoofing.
Critical Impact
Attackers can forge the source of cryptographically signed data, undermining trust boundaries in Liman MYS and enabling downstream attacks on confidentiality, integrity, and availability.
Affected Products
- HAVELSAN Liman MYS versions before Master.1107
Discovery Timeline
- 2026-07-07 - CVE-2026-11348 published to NVD
- 2026-07-07 - Last updated in NVD database
Technical Details for CVE-2026-11348
Vulnerability Analysis
CVE-2026-11348 stems from improper verification of a cryptographic signature within Liman MYS. When the application receives signed data, it fails to correctly validate the signature against the expected signer. An attacker able to reach the affected component over the network can supply crafted payloads that the application accepts as authentic.
Because the signature check does not enforce proper cryptographic binding between signer and payload, the affected code path treats attacker-controlled input as trusted. This breaks the guarantees that signature verification normally provides and allows the attacker to impersonate a legitimate data source.
The classification under [CWE-347] Improper Verification of Cryptographic Signature indicates a design or implementation defect in the verification logic itself, rather than key compromise. Common root causes for this class include accepting unsigned or partially signed messages, not validating the certificate chain, using weak or misconfigured algorithms, or failing to bind the signature to the specific message context.
Root Cause
The root cause is a defect in how Liman MYS verifies cryptographic signatures on incoming data. The verification routine does not sufficiently prove that the received payload was signed by the expected authority, allowing forged or replayed content to pass validation.
Attack Vector
Exploitation occurs over the network. No authentication or user interaction is required, but attack complexity is high, indicating that the attacker must satisfy specific conditions such as timing, message structure, or interception of legitimate traffic. Once successful, the attacker can inject data that the application processes as if it originated from a trusted source.
No verified public exploit code is available. Technical details are referenced in the Siber Güvenlik Notification TR-26-0504.
Detection Methods for CVE-2026-11348
Indicators of Compromise
- Unexpected data updates or configuration changes within Liman MYS originating from unverified or unusual network sources
- Signed messages processed by Liman MYS that lack a matching entry in upstream signer or certificate authority logs
- Anomalous network traffic to Liman MYS management endpoints from hosts that do not normally communicate with the platform
Detection Strategies
- Inspect Liman MYS application and audit logs for signature verification events and correlate them against known-good signer identities
- Monitor network flows to Liman MYS instances for TLS anomalies, unexpected peers, or traffic patterns inconsistent with baseline management activity
- Alert on Liman MYS actions triggered by data ingestion events that cannot be attributed to a documented, authenticated source
Monitoring Recommendations
- Forward Liman MYS logs to a centralized analytics platform to enable correlation of signature-related events with broader network telemetry
- Baseline normal signer identities and message frequencies, and alert on deviations such as new signers, off-hours activity, or bursts of signed messages
- Track deployed Liman MYS versions across the environment to confirm all instances are upgraded to Master.1107 or later
How to Mitigate CVE-2026-11348
Immediate Actions Required
- Upgrade all Liman MYS deployments to release Master.1107 or later as published by HAVELSAN
- Restrict network access to Liman MYS management interfaces to a defined set of trusted administrative sources
- Review recent Liman MYS activity for signs of data or configuration changes accepted from unverified sources
Patch Information
HAVELSAN addresses the improper signature verification issue in Liman MYS release Master.1107. Refer to the Siber Güvenlik Notification TR-26-0504 for the vendor advisory and upgrade guidance.
Workarounds
- Place Liman MYS behind network segmentation and firewall rules that permit inbound connections only from authorized peers until patching is complete
- Enforce mutual TLS or an additional transport-layer authentication mechanism between Liman MYS and upstream data sources where supported
- Increase logging verbosity for signature verification and data ingestion events to enable rapid identification of exploitation attempts
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
