# CVE-2026-46562: Yamcs: Remote Code Execution via Mission Database algorithm override

> Attackers can execute arbitrary OS commands via JavaScript injection in Yamcs mission database algorithms, especially when default guest access is enabled.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Jul 2026
- **Updated:** 16 Jul 2026
- **Also known as:** GHSA-vmwp-vh32-rj75

## What is CVE-2026-46562?

CVE-2026-46562 is a critical code injection vulnerability in yamcs, published on 16 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Yamcs is a mission control framework. Prior to 5.12.7, the Nashorn ScriptEngine used to evaluate user-supplied JavaScript algorithm text in yamcs-core/src/main/java/org/yamcs/algorithms/ScriptAlgorithmExecutorFactory.java was constructed without a ClassFilter, so a user with the ChangeMissionDatabase privilege could override an algorithm through the MdbOverrideApi.updateAlgorithm endpoint and supply JavaScript that reaches arbitrary Java classes (for example Java.type("java.lang.Runtime").getRuntime().exec(...)) to execute arbitrary OS commands as the Yamcs process; in the default configuration with no security.yaml the built-in guest user has superuser=true, making the issue reachable without authentication. This issue is fixed in versions 5.12.7 and 5.13.0, which disable algorithm editing by default.

Weakness: CWE-94 (Improper Control of Generation of Code), CWE-95 (Improper Neutralization of Directives in Dynamically Evaluated Code), CWE-470 (Use of Externally-Controlled Input to Select Classes or Code)

## Which versions are affected by CVE-2026-46562?

2 open source packages ship an affected version, including org.yamcs:yamcs-core. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.yamcs:yamcs-core` | Maven | All versions | 5.12.7 |
| `org.yamcs:yamcs-core` | Maven | All versions | 5.12.7 |

Products: Spaceapplications Yamcs.

## How do I fix CVE-2026-46562?

Upgrade org.yamcs:yamcs-core to 5.12.7 or later.

## Is CVE-2026-46562 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-46562 exists.

## Other vulnerabilities in yamcs

- [CVE-2026-44632](https://insights.sbomify.com/CVE-2026-44632/): Yamcs: Server-Side Code Injection (RCE) via Janino Expression Engine in `JavaExprAlgorithmExecutionFactory` (critical 9.1)
- [CVE-2026-46621](https://insights.sbomify.com/CVE-2026-46621/): Yamcs: Authenticated Remote Code Execution (RCE) via Jython Algorithm Code Injection (critical 9.1)
- [CVE-2023-45278](https://insights.sbomify.com/CVE-2023-45278/): Yamcs API Directory Traversal vulnerability (critical 9.1)
- [CVE-2023-45277](https://insights.sbomify.com/CVE-2023-45277/): Yamcs Path Traversal vulnerability (high 7.5)
- [CVE-2026-44596](https://insights.sbomify.com/CVE-2026-44596/): Yamcs: No Rate Limiting on Authentication Endpoint (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-46562 and fix it if it is affected.

What it is: CVE-2026-46562 is a critical code injection vulnerability in yamcs, published on 16 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-46562 exists.

Affected packages and fixed versions:
- org.yamcs:yamcs-core (Maven): affected all versions; fixed in 5.12.7
- org.yamcs:yamcs-core (Maven): affected all versions; fixed in 5.12.7

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-46562/ (Markdown: https://insights.sbomify.com/CVE-2026-46562/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-46562
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46562
- OSV: https://osv.dev/vulnerability/CVE-2026-46562

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-46562/
Summaries are generated and may contain mistakes; the official description above is the record.