CVE-2026-46621

CRITICALPre-NVD 9.19.1
EchelonGraph scoreLOW confidence

This critical-severity CVE scores 9.1 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit probability: 0.5%, top 35% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: cna:github_m, epss
Elevated
9.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 9.1Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Yamcs is a mission control framework. Prior to 5.12.7, the Yamcs script evaluation engine for Python algorithms dynamically compiled and evaluated user-controlled algorithm text using Jython through the JSR-223 ScriptEngine API without enforcing a secure sandbox, so an authenticated user with the ChangeMissionDatabase privilege could override an existing Python algorithm's logic through the mission database REST API and import and execute arbitrary Java classes such as java.lang.Runtime to achieve remote code execution on the underlying host operating system. This issue is fixed in versions 5.12.7 and 5.13.0, which disable algorithm editing by default.

CVSS v3
9.1
EG Score
9.1(low)
EPSS
65.3%
KEV
Not listed

Published

May 27, 2026

Last Modified

July 16, 2026

Advisory Details (5)

Auto-updated Jul 16, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_release, github.
github_release Patch Available

Yamcs 5.13.0

Patch available: yamcs/yamcs yamcs-5.13.0

https://github.com/yamcs/yamcs/releases/tag/yamcs-5.13.0
github_release Patch Available

Yamcs 5.12.7

Patch available: yamcs/yamcs yamcs-5.12.7

https://github.com/yamcs/yamcs/releases/tag/yamcs-5.12.7
github_commit

commit 4ff8fda642ea (yamcs/yamcs)

Fix landed in yamcs/yamcs commit 4ff8fda642ea — awaiting tagged release

https://github.com/yamcs/yamcs/commit/4ff8fda642ea8c3309a4d3f379aa77b763148992
github_commit

commit 3c550348f866 (yamcs/yamcs)

Fix landed in yamcs/yamcs commit 3c550348f866 — awaiting tagged release

https://github.com/yamcs/yamcs/commit/3c550348f866af4675d2ba4a51d8d12b7c7c6011
github Patch Available🟡 PoC Available

Authenticated Remote Code Execution (RCE) via Jython Algorithm Code Injection · Advisory · yamcs/yamcs · GitHub

https://github.com/yamcs/yamcs/security/advisories/GHSA-2g95-6x5q-xjwj

Vendor Advisories for CVE-2026-46621(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Maven(1)
PackageVulnerable rangeFixed inDependents
org.yamcs:yamcs-core0.29.3 ... 5.9.9 (165 versions)5.12.7—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 2× in last 7d / 40× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 143 total refreshes for this CVE.

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Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-46621?
CVE-2026-46621 is a critical vulnerability published on May 27, 2026. Yamcs is a mission control framework. Prior to 5.12.7, the Yamcs script evaluation engine for Python algorithms dynamically compiled and evaluated user-controlled algorithm text using Jython through the JSR-223 ScriptEngine API without enforcing a secure sandbox, so an authenticated user with the…
When was CVE-2026-46621 disclosed?
CVE-2026-46621 was first published in the National Vulnerability Database on May 27, 2026, with the most recent update on July 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-46621 actively exploited?
CVE-2026-46621 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 65.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-46621?
CVE-2026-46621 has a CVSS v3 base score of 9.1 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-46621?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-46621, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-46621

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