Vulnerability · Published Jul 16, 2026 · Assigned by GitHub_M

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

Medium 4.3

In plain English

A medium-severity missing authorization in yamcs from yamcs. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 65% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)4.3Medium

Exploit odds (30 days)1.1%top 35.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack tooling1Public PoC

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Maven	org.yamcs:yamcs-core	5.12.7	GHSA-p2rj-mrmc-9w29

Affected products (as reported)

Vendor	Product	Versions
yamcs	yamcs	< 5.12.7

Weakness: CWE-862 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

References

https://github.com/yamcs/yamcs/security/advisories/GHSA-p2rj-mrmc-9w29 x_refsource_CONFIRM
https://github.com/yamcs/yamcs/commit/0e12b518f103f24681299318a30a460fe4327b88 x_refsource_MISC
https://github.com/yamcs/yamcs/commit/e90099fba98e96214217c195b6a5b87b5f46e51c x_refsource_MISC
https://github.com/yamcs/yamcs/releases/tag/yamcs-5.12.7 x_refsource_MISC
https://github.com/yamcs/yamcs/releases/tag/yamcs-5.13.0 x_refsource_MISC