Path Traversal in Yamcs

CVE-2026-55552

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.

Vulnerability class: Path Traversal (Directory Traversal)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.017 (76.9th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 77th percentile — 76.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-55552: rose from 0.004 to 0.017.

EPSS over last 30 days · oldest: 0.004 · newest: 0.017 · change: +0.013

Affected products

  • Yamcs — versions < 5.12.0

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-55552?
CVE-2026-55552 is a high-severity vulnerability in Yamcs, classified under Path Traversal. CVSS score: 7.5/10. Published 2026-08-28.
How severe is CVE-2026-55552?
High severity. CVSS v3 base score is 7.5 out of 10.