What’s Vulnerable › Vulnerabilities

CVE-2026-46621: Yamcs: Authenticated Remote Code Execution (RCE) via Jython Algorithm Code Injection

• Severity: critical (CVSS 9.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.1% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-07-16 · updated 2026-07-20
• Weakness: CWE-94

Description

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.

Affected products

• yamcs: before 5.12.7 — fixed in 5.12.7

How to fix

Upgrade to a fixed version: yamcs 5.12.7. Check the vendor advisory for mitigations.

References

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

Get alerted when CVE-2026-46621 or the next vulnerability affects your stack