RCE in Yamcs

CVE-2026-55511

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.

Vulnerability class: RCE (Remote Code Execution)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.007 (50.9th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 51st percentile — 50.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-55511: held from 0.007 to 0.007.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: -0.000

Affected products

  • Yamcs — versions < 5.12.8, >= 5.13.0, < 5.13.2

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-55511?
CVE-2026-55511 is a critical-severity vulnerability in Yamcs, classified under Code Injection. CVSS score: 9.1/10. Published 2026-08-28.
How severe is CVE-2026-55511?
Critical severity. CVSS v3 base score is 9.1 out of 10.
Is CVE-2026-55511 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.