CVE-2026-55545

Received Received - Intake

WebSocket Privilege Escalation in Yamcs

Publication date: 2026-08-28

Last updated on: 2026-08-28

Assigner: GitHub, Inc.

Description

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.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-08-28

Last Modified

2026-08-28

Generated

2026-08-29

AI Q&A

2026-08-29

EPSS Evaluated

N/A

NVD

CVE-2026-55545

EUVD

EUVD-2026-67839

Affected Vendors & Products

Vendor	Product	Version / Range
yamcs	yamcs	to 5.13.2 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-862	The product does not perform an authorization check when an actor attempts to access a resource or perform an action.

Attack-Flow Graph

Executive Summary

CVE-2026-55545 is a vulnerability in Yamcs where WebSocket subscription handlers lack proper privilege checks that are enforced in REST API endpoints. This allows low-privilege authenticated users to access restricted data like telemetry packets, algorithm status, and mission database changes through WebSocket connections without required permissions.

Impact Analysis

Unauthorized users could access sensitive mission data, telemetry packets, algorithm status, or mission database changes. This could lead to data leaks, unauthorized system monitoring, or misuse of restricted information if the system is not patched to versions 5.12.8 or 5.13.2.

Mitigation Strategies

Upgrade Yamcs to version 5.12.8 or later, or 5.13.2 or later to apply the missing WebSocket privilege checks. Verify that WebSocket subscriptions now enforce the same permissions as REST endpoints for packets, algorithm status, and mission database changes.

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