CVE-2026-55521Public exploitNetwork attack vectorHinoki check available

Authenticated telemetry disclosure and control manipulation

Published Aug 28, 2026 · Updated Aug 28, 2026

Missing authorization in the Yamcs Core API before 5.12.8 and 5.13.0 through 5.13.1 allows remote authenticated users to alter operations. IndexesApi returns packet and event index metadata without ReadPacket checks, while Cop1Api and TimeApi change link state and simulation time without required system-privilege checks. Any authenticated account, including an unprivileged Guest, can disclose telemetry metadata, disrupt telecommand handling, or distort simulation-dependent processing.

CVSS severity8.8
High
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Missing authorization in the Yamcs Core API before 5.12.8 and 5.13.0 through 5.13.1 allows remote authenticated users to alter operations. IndexesApi returns packet and event index metadata without ReadPacket checks, while Cop1Api and TimeApi change link state and simulation time without required system-privilege checks. Any authenticated account, including an unprivileged Guest, can disclose telemetry metadata, disrupt telecommand handling, or distort simulation-dependent processing.

The record

CVE
CVE-2026-55521
Published
Aug 28, 2026
Updated
Aug 28, 2026
Vendor
Space Applications Services
Product
Yamcs
Classifications
CWE-862, T1565.003
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 5.12.8
  2. Affected versionversion=>= 5.13.0, < 5.13.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Space Applications Services · Yamcsversion=< 5.12.8; version=>= 5.13.0, < 5.13.2

Published CVSS scores

8.8GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-862Missing Authorization
T1565.003Runtime Data Manipulation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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