Yamcs's Missing Authorization on Role and Privilege Enumeration Endpoints Allows Any Authenticated User to Disclose Full Security Configuration

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

4.3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

EPSS

• CVE-2026-55547: 0.34% estimated exploitation activity in the next 30 days; percentile 27.81 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Missing authorization checks on three IAM API endpoints (GET /api/roles, GET /api/roles/{name}, GET /api/privileges) allow any authenticated user — regardless of their assigned permissions — to enumerate the complete list of system privileges and role definitions. An attacker with only a low-privilege account (e.g., a read-only operator) can retrieve the full privilege taxonomy of the server, including the names and assignments of all administrator-level capabilities. This information directly enables targeted privilege escalation attacks. --- Details Three handler methods in IamApi.java serve sensitive security metadata without performing any authorization check: File: yamcs-core/src/main/java/org/yamcs/http/api/IamApi.java By contrast, all write operations and user-management endpoints in the same file correctly enforce authorization. For example: The three vulnerable endpoints share the same ControlAccess protection requirement as the user-management endpoints but were…

Published by the source

28 Aug 2026, 17:13 UTC

Last modified by the source

28 Aug 2026, 17:40 UTC

Source last checked

26 Oct 2026, 16:55 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-cvw4-55pp-3hfq

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-cvw4-55pp-3hfq

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# Patch Next advisory brief: CVE-2026-55547

Advisory: Yamcs's Missing Authorization on Role and Privilege Enumeration Endpoints Allows Any Authenticated User to Disclose Full Security Configuration
IDs: CVE-2026-55547, GHSA-cvw4-55pp-3hfq
Record: https://patchnext.com/advisories/cve-2026-55547 (revision 2, source checked 26 Oct 2026, 16:55 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 4.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.yamcs:yamcs-core 5.13.2, 5.12.8. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.yamcs:yamcs-core: affected >= 5.13.0, <= 5.13.1; <= 5.12.7; fixed in 5.12.8, 5.13.2

## Suggested inspection (read-only)
- Maven org.yamcs:yamcs-core: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.yamcs:yamcs-core.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-cvw4-55pp-3hfq (OSV record GHSA-cvw4-55pp-3hfq lists affected ranges: Maven org.yamcs:yamcs-core >=5.13.0 =0 <5.12.8 (fixed))
- Verified: https://github.com/advisories/GHSA-cvw4-55pp-3hfq (GitHub-reviewed advisory GHSA-cvw4-55pp-3hfq lists affected ranges: Maven org.yamcs:yamcs-core >=5.13.0 =0 <=5.12.7)

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