CVE-2026-55547 Yamcs's Missing Authorization on Role and Privilege Enumeration Endpoints Allows Any Authenticated User to Disclose Full Security Configuration
Authenticated users can enumerate system roles and privileges due to missing authorization checks, exposing security configuration details.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-55547?
CVE-2026-55547 is a medium-severity missing authorization vulnerability in yamcs, published on 28 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-55547?
4 open source packages ship an affected version, including org.yamcs:yamcs-core.
| Package | Affected | Fixed in |
|---|---|---|
org.yamcs:yamcs-core Maven | All versions | 5.12.8 |
org.yamcs:yamcs-core Maven | All versions | 5.12.8 |
org.yamcs:yamcs-core Maven | From 5.13.0 | 5.13.2 |
org.yamcs:yamcs-core Maven | From 5.13.0 | 5.13.2 |
How do I fix CVE-2026-55547?
Upgrade org.yamcs:yamcs-core to a fixed version for your release line: 5.12.8 or 5.13.2.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-55547 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55547 exists.
Sources
Also known as GHSA-cvw4-55pp-3hfq.