RCE in Yamcs

CVE-2026-55565

Yamcs is a mission control framework. Prior to 5.12.8 and 5.13.2, Yamcs LikeExpression.fillCode_getValueReturn in yamcs-core/src/main/java/org/yamcs/yarch/streamsql/LikeExpression.java inserts an unescaped LIKE pattern into Java source compiled by Expression.getCompiledExpression through SimpleCompiler.cook instead of applying ValueExpression.escapeJavaString. The pattern can originate from POST /api/archive/{instance}:executeSql, POST /api/archive/{instance}:streamSql, POST /api/archive/{instance}/tables/{table}:readRows, GET /api/archive/{instance}/events, or activity searches, including paths available with ReadTables, ReadEvents, or ReadActivities. A quote in the pattern can inject Java that runs as the Yamcs server process. 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 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.006 (49.7th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 49.7% 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-2026-55565: held from 0.005 to 0.006.

EPSS over last 30 days · oldest: 0.005 · newest: 0.006 · change: +0.002

Affected products

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

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-55565?
CVE-2026-55565 is a critical-severity vulnerability in Yamcs, classified under Code Injection. CVSS score: 9.9/10. Published 2026-08-28.
How severe is CVE-2026-55565?
Critical severity. CVSS v3 base score is 9.9 out of 10.