CVE-2026-46621

CRITICAL 9.1

Yamcs: Authenticated Remote Code Execution (RCE) via Jython Algorithm Code Injection

CVSS Score

9.1

EPSS Score

0.0%

EPSS Percentile

0th

Yamcs is a mission control framework. Prior to 5.12.7, the Yamcs script evaluation engine for Python algorithms dynamically compiled and evaluated user-controlled algorithm text using Jython through the JSR-223 ScriptEngine API without enforcing a secure sandbox, so an authenticated user with the ChangeMissionDatabase privilege could override an existing Python algorithm's logic through the mission database REST API and import and execute arbitrary Java classes such as java.lang.Runtime to achieve remote code execution on the underlying host operating system. This issue is fixed in versions 5.12.7 and 5.13.0, which disable algorithm editing by default.

CWE	CWE-94
Vendor	yamcs
Product	yamcs
Published	Jul 16, 2026
Last Updated	Jul 16, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Affected Versions

yamcs / yamcs

< 5.12.7

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/yamcs/yamcs/security/advisories/GHSA-2g95-6x5q-xjwj github.com: https://github.com/yamcs/yamcs/commit/3c550348f866af4675d2ba4a51d8d12b7c7c6011 github.com: https://github.com/yamcs/yamcs/commit/4ff8fda642ea8c3309a4d3f379aa77b763148992 github.com: https://github.com/yamcs/yamcs/releases/tag/yamcs-5.12.7 github.com: https://github.com/yamcs/yamcs/releases/tag/yamcs-5.13.0