Vulnerability · Published Aug 28, 2026 · Assigned by GitHub_M

CVE-2026-55552Yamcs: Unauthenticated Directory Traversal

High 7.5

In plain English

A high-severity path traversal in yamcs from yamcs. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.7% (higher than 78% of all known vulnerabilities). Ready-made attack tooling exists: Nuclei. Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)1.7%top 22.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack tooling1Nuclei

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Maven	org.yamcs:yamcs-core	5.12.0	GHSA-9jg3-g3wh-w9pj

Affected products (as reported)

Vendor	Product	Versions
yamcs	yamcs	< 5.12.0

Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

References

https://github.com/yamcs/yamcs/security/advisories/GHSA-9jg3-g3wh-w9pj x_refsource_CONFIRM
https://github.com/yamcs/yamcs/commit/c7dfd24e469ae1086c23e0fe04401cb1ce4260d4 x_refsource_MISC
https://github.com/yamcs/yamcs/commit/f4bc588880c166849e983aa8f65b9c8107d06091 x_refsource_MISC
https://github.com/yamcs/yamcs/releases/tag/yamcs-5.11.13 x_refsource_MISC
https://github.com/yamcs/yamcs/releases/tag/yamcs-5.12.0 x_refsource_MISC