CVE-2026-46621

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 1.1%, top 36% 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: epss, secondary
Elevated
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.1Exploit: Elevated riskExposed: 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(medium)
EG Risk
57(Track*)
EG Risk 57/100SSVC: Track*

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity91% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
1%
EPSS %ILE
64%
KEV
Not listed

Published

May 27, 2026

Last Modified

July 20, 2026

Advisory Details (5)

Auto-updated Aug 29, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_release, github.
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
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

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 6× in last 7d / 44× 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.

  1. 2026-09-01 13:54 UTCEPSS rescore
  2. 2026-08-30 19:17 UTCEPSS rescore
  3. 2026-08-30 01:22 UTCEPSS rescore
  4. 2026-08-28 21:41 UTCEPSS rescore
  5. 2026-08-27 14:25 UTCEPSS rescore
  6. 2026-08-26 14:46 UTCEPSS rescore
  7. 2026-08-25 13:49 UTCEPSS rescore
  8. 2026-08-25 05:08 UTCEG score recompute
  9. 2026-08-23 14:51 UTCEG score recompute
  10. 2026-08-23 00:19 UTCEPSS rescore
  11. 2026-08-22 00:19 UTCEG score recompute
  12. 2026-08-21 23:49 UTCEPSS rescore
  13. 2026-08-21 01:19 UTCEG score recompute
  14. 2026-08-20 22:55 UTCEPSS rescore
  15. 2026-08-20 11:11 UTCEG score recompute
  16. 2026-08-19 17:04 UTCEPSS rescore
  17. 2026-08-18 13:48 UTCEPSS rescore
  18. 2026-08-17 13:47 UTCEPSS rescore
  19. 2026-08-16 15:12 UTCEG score recompute
  20. 2026-08-16 14:56 UTCEPSS rescore
  21. 2026-08-16 02:42 UTCEG score recompute
  22. 2026-08-16 02:14 UTCEPSS rescore
  23. 2026-08-15 03:34 UTCEG score recompute
  24. 2026-08-15 01:30 UTCEPSS rescore
  25. 2026-08-14 01:22 UTCEG score recompute
Show 46 more
  1. 2026-08-13 22:00 UTCEPSS rescore
  2. 2026-08-12 13:52 UTCEG score recompute
  3. 2026-08-12 13:51 UTCEPSS rescore
  4. 2026-08-11 18:29 UTCEG score recompute
  5. 2026-08-11 00:09 UTCEG score recompute
  6. 2026-08-11 00:00 UTCEPSS rescore
  7. 2026-08-09 14:05 UTCEG score recompute
  8. 2026-08-09 13:46 UTCEPSS rescore
  9. 2026-08-08 19:16 UTCEG score recompute
  10. 2026-08-08 16:37 UTCEPSS rescore
  11. 2026-08-07 18:58 UTCEG score recompute
  12. 2026-08-06 16:42 UTCEG score recompute
  13. 2026-08-06 13:47 UTCEPSS rescore
  14. 2026-08-05 20:50 UTCEG score recompute
  15. 2026-08-05 19:17 UTCEPSS rescore
  16. 2026-08-04 15:10 UTCEPSS rescore
  17. 2026-08-04 10:39 UTCEPSS rescore
  18. 2026-08-03 16:23 UTCEG score recompute
  19. 2026-08-03 10:36 UTCEPSS rescore
  20. 2026-08-02 06:00 UTCEG score recompute
  21. 2026-08-02 02:27 UTCEPSS rescore
  22. 2026-08-01 15:01 UTCEG score recompute
  23. 2026-08-01 04:16 UTCEPSS rescore
  24. 2026-07-31 07:04 UTCEG score recompute
  25. 2026-07-30 16:28 UTCEPSS rescore
  26. 2026-07-30 01:30 UTCEPSS rescore
  27. 2026-07-29 14:41 UTCEG score recompute
  28. 2026-07-28 15:36 UTCEPSS rescore
  29. 2026-07-27 14:13 UTCEPSS rescore
  30. 2026-07-27 09:56 UTCEG score recompute
  31. 2026-07-26 14:54 UTCEPSS rescore
  32. 2026-07-26 14:54 UTCEPSS rescore
  33. 2026-07-25 14:18 UTCEPSS rescore
  34. 2026-07-24 14:17 UTCEPSS rescore
  35. 2026-07-23 14:18 UTCEPSS rescore
  36. 2026-07-23 03:17 UTCEG score recompute
  37. 2026-07-22 14:08 UTCEPSS rescore
  38. 2026-07-21 15:24 UTCEPSS rescore
  39. 2026-07-20 17:08 UTCEPSS rescore
  40. 2026-07-19 14:31 UTCEPSS rescore
  41. 2026-07-19 02:29 UTCEPSS rescore
  42. 2026-07-18 10:04 UTCEPSS rescore
  43. 2026-06-14 23:18 UTCEPSS rescore
  44. 2026-06-13 23:00 UTCEPSS rescore
  45. 2026-06-12 23:12 UTCEPSS rescore
  46. 2026-05-27 23:03 UTCEG score recompute

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 20, 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 1% probability of exploitation in the next 30 days, which ranks it in the top 36.2% of all scored CVEs.
What is the CVSS score of CVE-2026-46621?
CVE-2026-46621 has a CVSS v3 base score of 9.1 (NVD).
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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