CVE-2026-55552 Yamcs: Unauthenticated Directory Traversal
Unauthenticated attackers can read arbitrary host files via path traversal in Yamcs mission control framework.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-55552?
CVE-2026-55552 is a high-severity path traversal vulnerability in yamcs, published on 28 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Yamcs is a mission control framework. Prior to 5.11.13, Yamcs StaticFileHandler.locateFile resolves an unauthenticated request path without using Path.normalize and Path.toAbsolutePath to confirm that the absolute path remains within the configured staticRoots. A path containing traversal segments can escape the intended web root and return an arbitrary readable host file. The flaw is in yamcs-core/src/main/java/org/yamcs/http/StaticFileHandler.java and can disclose sensitive operating-system and application data. This issue is fixed in version 5.11.13, and the 5.12 line is fixed from version 5.12.0.
Weakness: CWE-22
Which versions are affected by CVE-2026-55552?
2 open source packages ship an affected version, including org.yamcs:yamcs-core.
| Package | Affected | Fixed in |
|---|---|---|
org.yamcs:yamcs-core Maven | All versions | 5.12.0 |
org.yamcs:yamcs-core Maven | All versions | 5.12.0 |
How do I fix CVE-2026-55552?
Upgrade org.yamcs:yamcs-core to 5.12.0 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-55552 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55552 exists.
Public exploit code: 1 Nuclei template.
Sources
Also known as GHSA-9jg3-g3wh-w9pj.