---
title: "CVE-2026-55511: Yamcs vulnerable to authenticated RCE via StreamSQL aggregate-compiler column-name injection in Yamcs `executeSql`"
url: https://erroneo.us/security/cve/CVE-2026-55511/
description: "CVE-2026-55511 (org.yamcs:yamcs-core (Maven)): Yamcs is a mission control framework. Prior to 5.12.8 and 5.13.2, Yamcs allows a user with…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-08-28
date_modified: 2026-09-01
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-55511"
kev: false
cvss: 9.1
epss: 0.00677
license: All rights reserved. Quote with attribution and a link.
---

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

**Signal:** Critical, preconditions apply. Severe if exploited, but exploitation needs conditions that may not apply to you. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.7% , percentile 52: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 52% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Needs an account (high (admin)). Exposure depends on who can log in.
- Only applies if your dependency tree includes org.yamcs:yamcs-core (Maven) >= 5.13.0, <= 5.13.1, fixed in 5.13.2 ; org.yamcs:yamcs-core (Maven) <= 5.12.7, fixed in 5.12.8 . Check your lockfile, including transitive dependencies.

## What it is

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.fillCodeInputDefVars 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.

## Affected packages

- Maven `org.yamcs:yamcs-core` >= 5.13.0, <= 5.13.1 → fixed: 5.13.2
- Maven `org.yamcs:yamcs-core` <= 5.12.7 → fixed: 5.12.8

## Affected products (CVE record)

- yamcs yamcs: < 5.12.8, >= 5.13.0, < 5.13.2

## Severity

- GitHub_M CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.68% probability of exploitation activity in the next 30 days; percentile 52.

## Sources

- [GitHub Advisory GHSA-3g44-3m7x-cgg2](https://github.com/advisories/GHSA-3g44-3m7x-cgg2)
- [CVE.org record CVE-2026-55511](https://www.cve.org/CVERecord?id=CVE-2026-55511)
- [NVD entry CVE-2026-55511](https://nvd.nist.gov/vuln/detail/CVE-2026-55511)
- [github.com](https://github.com/yamcs/yamcs/security/advisories/GHSA-3g44-3m7x-cgg2)
- [github.com](https://github.com/yamcs/yamcs/commit/8c1070b12c0a6c003903325cb2a1013347e2dbde)
- [github.com](https://github.com/yamcs/yamcs/commit/b65a3d78178ba99a58b753feda6ecc3b5a694f13)
- [github.com](https://github.com/yamcs/yamcs/releases/tag/yamcs-5.12.8)
- [github.com](https://github.com/yamcs/yamcs/releases/tag/yamcs-5.13.2)

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Source page: https://erroneo.us/security/cve/CVE-2026-55511/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt