CVE-2026-44595

Yamcs: Unauthorized user enumeration via IAM API endpoints

CVSS 4.3 MEDIUMCWE-862

Vexday Risk Score

30Low

SSVC decision (CISA)

Attend

PoC available → attend closely

Exploit maturity

Proof of concept

Public proof of concept exists, but not yet automated.

CVSS 4.3EPSS —KEV nãoPoC públicaNuclei —Metasploit —Patch —

Lifecycle

29 May 2026Public PoC

16 Jul 2026Published on NVD

Recommendation: Plan a near-term fix — a public PoC already exists.

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.

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

Affected products

yamcs · yamcs

public PoCs found — 2

githubgithub.com/ex-cal1bur/CVE-2026-44595★ 0 exploitdbwww.exploit-db.com/exploits/52604unverified

⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.

References

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://github.com/yamcs/yamcs/security/advisories/GHSA-p2rj-mrmc-9w29