# CVE-2026-55511: Yamcs: Authenticated RCE via StreamSQL aggregate-compiler column-name injection in Yamcs `executeSql`

> Authenticated attackers with archiving privileges can inject Java code via StreamSQL column names to execute arbitrary commands in Yamcs.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Aug 2026
- **Updated:** 1 Sep 2026
- **Also known as:** GHSA-3g44-3m7x-cgg2

## What is CVE-2026-55511?

CVE-2026-55511 is a critical code injection vulnerability in yamcs, published on 28 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

Yamcs is a mission control framework. Prior to 5.12.8 and 5.13.2, Yamcs allows a user with SystemPrivilege.ControlArchiving to create a double-quoted StreamSQL column name that is interpolated into generated Java source by Expression.fillCode_InputDefVars and Expression.sanitizeName. A sum aggregate reaches yamcs-core/src/main/java/org/yamcs/yarch/streamsql/CompilableAggregateExpression.java and yamcs-core/src/main/java/org/yamcs/yarch/streamsql/funct/SumExpression.java through SelectExpression.compile, where Janino SimpleCompiler.cook compiles the injected source. POST /api/archive/{instance}:executeSql can therefore execute arbitrary Java in the Yamcs server process, exposing mission data and credentials and permitting telemetry tampering or denial of service. This issue is fixed in versions 5.12.8 and 5.13.2.

Weakness: CWE-94 (Improper Control of Generation of Code)

## Which versions are affected by CVE-2026-55511?

4 open source packages ship an affected version, including org.yamcs:yamcs-core.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.yamcs:yamcs-core` | Maven | All versions | 5.12.8 |
| `org.yamcs:yamcs-core` | Maven | All versions | 5.12.8 |
| `org.yamcs:yamcs-core` | Maven | From 5.13.0 | 5.13.2 |
| `org.yamcs:yamcs-core` | Maven | From 5.13.0 | 5.13.2 |

## How do I fix CVE-2026-55511?

Upgrade org.yamcs:yamcs-core to a fixed version for your release line: 5.12.8 or 5.13.2.

## Is CVE-2026-55511 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55511 exists.

Public exploit code:

- Remote Code Execution (RCE) in Yamcs Mission Control System via Java Statement Injection in Yarch SQL Double-Quoted IdentifiersRemote Code Execution (RCE) in Yamcs Mission Control System via Java Statement Injection in Yarch SQL Double-Quoted Identifiers (github_poc): https://github.com/junfuture1103/CVE-2026-55511

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-55511 and fix it if it is affected.

What it is: CVE-2026-55511 is a critical code injection vulnerability in yamcs, published on 28 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55511 exists.

Affected packages and fixed versions:
- org.yamcs:yamcs-core (Maven): affected all versions; fixed in 5.12.8
- org.yamcs:yamcs-core (Maven): affected all versions; fixed in 5.12.8
- org.yamcs:yamcs-core (Maven): affected from 5.13.0; fixed in 5.13.2
- org.yamcs:yamcs-core (Maven): affected from 5.13.0; fixed in 5.13.2

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-2026-55511/ (Markdown: https://insights.sbomify.com/CVE-2026-55511/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55511
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55511
- OSV: https://osv.dev/vulnerability/CVE-2026-55511

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-55511/
Summaries are generated and may contain mistakes; the official description above is the record.