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Fencer Vulns
medium 4.3

CVE-2026-44595 json

Yamcs: Unauthorized user enumeration via IAM API endpoints

published 2026-05-27 5 mo ago modified 2026-07-18 3 mo ago also GHSA-p2rj-mrmc-9w29 , EUVD-2026-44954

cvss
4.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 64%
public exploits
1
Exploit-DB

Summary

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.

Patch / fix

  • maven org.yamcs:yamcs-core 5.12.7
  • spaceapplications yamcs 5.12.7

Timeline

  1. Published
  2. First public exploit (EDB-52604)

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

1.06% chance of exploitation in the next 30 days, higher than 64% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • EDB-52604 YAMCS yamcs-core 5.12.7 - User Enumeration webapps, 2026-05-30
  • github.com https://github.com/yamcs/yamcs/security/advisories/GHSA-p2rj-mrmc-9w29 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
GitHub 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
maven org.yamcs:yamcs-core
<5.12.7
5.12.7

Affected products

  • yamcs yamcs

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.