Yamcs up to 5.12.7/5.13.1 WebSocket Subscription improper authorization

Summaryinfo

A vulnerability was found in Yamcs up to 5.12.7/5.13.1. It has been classified as problematic. This impacts an unknown function of the component WebSocket Subscription Handler. The manipulation leads to improper authorization. This vulnerability is traded as CVE-2026-55545. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in Yamcs up to 5.12.7/5.13.1 and classified as problematic. This issue affects an unknown code block of the component WebSocket Subscription Handler. The manipulation with an unknown input leads to a improper authorization vulnerability. Using CWE to declare the problem leads to CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. Impacted is confidentiality. The summary by CVE is:

Yamcs is a mission control framework. Prior to 5.12.8 and 5.13.2, Yamcs WebSocket subscription handlers fail to enforce the privileges required by equivalent REST endpoints. PacketsApi.subscribePackets exposes the packets WebSocket topic without ObjectPrivilegeType.ReadPacket, ProcessingApi.subscribeAlgorithmStatus exposes the algorithm-status WebSocket topic without ObjectPrivilegeType.ReadAlgorithm, and MdbOverrideApi.subscribeMdbChanges exposes the mdb-changes WebSocket topic without SystemPrivilege.GetMissionDatabase. A low-privilege authenticated user can receive telemetry packets, algorithm status, and mission database change information outside the assigned authorization scope. This issue is fixed in versions 5.12.8 and 5.13.2.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-55545 since 06/17/2026. The exploitation is known to be easy. The attack may be initiated remotely. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1548.002 according to MITRE ATT&CK.

Upgrading to version 5.12.8 or 5.13.2 eliminates this vulnerability.

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Productinfo

Name

• Yamcs

Version

• 5.12.0
• 5.12.1
• 5.12.2
• 5.12.3
• 5.12.4
• 5.12.5
• 5.12.6
• 5.12.7
• 5.13.0
• 5.13.1

Website

• Product: https://github.com/yamcs/yamcs/

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