Yamcs Vulnerable to Remote Code Execution via Mission Database algorithm override

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-46562: 0.98% estimated exploitation activity in the next 30 days; percentile 62.15 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Remote Code Execution via Mission Database algorithm override Summary The Nashorn ScriptEngine used to evaluate user-supplied algorithm text in MdbOverrideApi.updateAlgorithm is constructed without a ClassFilter, allowing a user with the ChangeMissionDatabase privilege to execute arbitrary Java code on the Yamcs server. In Yamcs's default configuration (no security.yaml), the built-in guest user has superuser=true, so the vulnerability is reachable without authentication. Details Vulnerable file: yamcs-core/src/main/java/org/yamcs/algorithms/ScriptAlgorithmExecutorFactory.java NashornScriptEngineFactory.getScriptEngine() accepts an optional ClassFilter that restricts which classes JavaScript can reach via Java.type(...). Yamcs passes no filter, so attacker-supplied JavaScript can reach any Java class — for example, Java.type("java.lang.Runtime").getRuntime().exec(...) runs arbitrary OS commands inside the Yamcs JVM. The path from HTTP request to eval is:…

Published by the source

27 May 2026, 22:45 UTC

Last modified by the source

27 May 2026, 22:45 UTC

Source last checked

26 Oct 2026, 16:45 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-vmwp-vh32-rj75

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# Patch Next advisory brief: CVE-2026-46562

Advisory: Yamcs Vulnerable to Remote Code Execution via Mission Database algorithm override
IDs: CVE-2026-46562, GHSA-vmwp-vh32-rj75
Record: https://patchnext.com/advisories/cve-2026-46562 (revision 1, source checked 26 Oct 2026, 16:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.yamcs:yamcs-core 5.12.7. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.yamcs:yamcs-core: affected < 5.12.7; fixed in 5.12.7

## Suggested inspection (read-only)
- Maven org.yamcs:yamcs-core: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.yamcs:yamcs-core.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-vmwp-vh32-rj75 (GitHub-reviewed advisory GHSA-vmwp-vh32-rj75 lists affected ranges: Maven org.yamcs:yamcs-core >=0 <5.12.7)

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