GHSA-fwww-cp23-7f5g

Source

https://github.com/advisories/GHSA-fwww-cp23-7f5g

Import Source

https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-fwww-cp23-7f5g/GHSA-fwww-cp23-7f5g.json

JSON Data

https://api.osv.dev/v1/vulns/GHSA-fwww-cp23-7f5g

Aliases

CVE-2026-55545

Published

2026-08-28T17:10:26Z

Modified

2026-08-28T17:25:37Z

Severity

6.5 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N CVSS Calculator

Summary

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

Details

Asset / scope: Yamcs 5.12.7 WebSocket topics (packets, algorithm-status, mdb-changes)

Summary

Several WebSocket subscription handlers do not perform the privilege check that their REST counterparts enforce, so a principal subscribing over WebSocket receives data the REST API would have scoped or denied.

Root cause

packets (PacketsApi.subscribePackets) performs no ReadPacket check, while the REST siblings do (listPackets:128, streamPackets:256, subscribeContainers:538). A principal with a narrow ReadPacket scope receives the raw binary of all TM packets on the processor.
algorithm-status (ProcessingApi.subscribeAlgorithmStatus) performs no check, while REST getAlgorithmStatus enforces checkObjectPrivileges(ReadAlgorithm, ...) (:467).
mdb-changes (MdbOverrideApi.subscribeMdbChanges) performs no check, while base MDB reads require GetMissionDatabase.

Remediation

Bring each WebSocket subscription handler to parity with its REST sibling's privilege check (ReadPacket, ReadAlgorithm, GetMissionDatabase). This is the same declarative fail-closed fix as Report 1.

Supporting material

Subsystem source audit of the WS-vs-REST authorization parity. Available on request.

Disclosure and credit

This was found by Cipher / Causal Security - https://causalsecurity.com/. We are coordinating disclosure via this report and request CVEs where you agree they qualify. We propose the 90-day window stated in your security policy. We might publish a write-up after a fix and the agreed window.

Database specific

{
    "cwe_ids":  [
        "CWE-862"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2026-08-28T17:10:26Z",
    "nvd_published_at":  null,
    "severity":  "MODERATE"
}

References

Affected packages

Maven / org.yamcs:yamcs-core

Package

Name: org.yamcs:yamcs-core; View open source insights on deps.dev
Purl: pkg:maven/org.yamcs/yamcs-core

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0 Unknown introduced version / All previous versions are affected

Fixed

5.12.8

Affected versions

0.*

0.29.3

0.30.0

3.*

3.0.0

3.1.0

3.1.1

3.1.2

3.2.0

3.2.1

3.2.2

3.3.0

3.3.1

3.4.0

3.4.1

3.4.2

3.4.3

3.4.4

3.4.5

3.4.6

3.4.8

3.4.11

4.*

4.0.0

4.0.1

4.1.1

4.1.2

4.2.0

4.2.1

4.2.2

4.3.0

4.3.1

4.4.0

4.4.1

4.4.2

4.5.0

4.6.0

4.6.1

4.6.2

4.6.3

4.7

4.7.1

4.7.3

4.8.0

4.8.1

4.9.0

4.9.1

4.9.2

4.9.3

4.9.4

4.10.0

4.10.1

4.10.2

4.10.3

4.10.4

4.10.5

4.10.6

4.10.7

4.10.8

4.10.9

5.*

5.0.0

5.1.0

5.1.1

5.1.2

5.1.3

5.1.4

5.2.0

5.2.1

5.2.2

5.2.3

5.2.4

5.2.5

5.2.6

5.3.0

5.3.1

5.3.2

5.3.3

5.3.4

5.3.5

5.3.6

5.4.0

5.4.1

5.4.2

5.4.3

5.4.4

5.4.5

5.5.0

5.5.1

5.5.2

5.5.3

5.5.4

5.5.5

5.5.6

5.5.7

5.6.0

5.6.1

5.6.2

5.7.0

5.7.1

5.7.2

5.7.3

5.7.4

5.7.5

5.7.6

5.7.7

5.7.8

5.7.9

5.7.10

5.7.11

5.7.12

5.7.13

5.8.0

5.8.1

5.8.2

5.8.3

5.8.4

5.8.5

5.8.6

5.8.7

5.8.8

5.9.0

5.9.1

5.9.2

5.9.3

5.9.4

5.9.5

5.9.6

5.9.7

5.9.8

5.9.8.1

5.9.9

5.9.10

5.9.11

5.9.12

5.10.0

5.10.1

5.10.2

5.10.3

5.10.4

5.10.5

5.10.6

5.10.7

5.10.8

5.10.9

5.10.10

5.10.11

5.10.12

5.11.0

5.11.1

5.11.2

5.11.3

5.11.4

5.11.5

5.11.6

5.11.7

5.11.8

5.11.9

5.11.10

5.11.11

5.11.12

5.11.13

5.12.0

5.12.1

5.12.2

5.12.3

5.12.4

5.12.5

5.12.6

5.12.7

Database specific

last_known_affected_version_range

"<= 5.12.7"

source

"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-fwww-cp23-7f5g/GHSA-fwww-cp23-7f5g.json"