CVE-2026-55521

Yamcs : Multiple Missing Function Level Access Control vulnerabilities in Yamcs Core API

HIGH
8.8
CVSS Score
Published: August 28, 2026 at 05:08 PM UTC
Updated: September 8, 2026 at 09:19 PM UTC
1 product affected across 1 vendorYamcs

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Severity
HIGH8.8
Exploit prediction
EPSS 0.5%
SSVC
PoC

Description

Yamcs is a mission control framework. Prior to 5.12.8 and 5.13.2, Yamcs omits authorization checks in IndexesApi.listPacketIndex, IndexesApi.listEventIndex, Cop1Api.disable, Cop1Api.resume, Cop1Api.initialize, Cop1Api.updateConfig, and TimeApi.setTime. An authenticated low-privilege user can read packet and event index metadata without ObjectPrivilegeType.ReadPacket, alter COP-1 link state without SystemPrivilege.ControlLinks, and manipulate simulation time. These operations can disclose telemetry metadata, disrupt telecommand handling, and affect system integrity and availability. 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

SSVCPoCNot automatableTotal impact

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

CVSS

8.8HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-862

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