CVE-2026-55545

Yamcs: WebSocket subscription handlers omit the privilege checks their REST siblings enforce

MEDIUM
6.5
CVSS Score
Published: August 28, 2026 at 05:09 PM UTC
Updated: September 8, 2026 at 09:19 PM UTC
1 product affected across 1 vendorYamcs

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 5.12.8v < 5.13.2
Affected range stops below 5.12.8, so it looks safe — our inference, not a vendor statement
Affected range stops below 5.13.2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-862

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