CVE-2026-46339

CRITICALPre-NVD 10.010.0—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 10.0 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 2.4%, top 17% 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
10.0EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 3%CVSS: 10.0Exploit: Elevated riskExposed: 0

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

9Router is an AI router & token saver. From 0.4.30 until 0.4.37, 9Router's src/proxy.js middleware did not protect /api/cli-tools/* and /api/mcp/*, allowing unauthenticated registration of customPlugins through src/app/api/cli-tools/cowork-settings/route.js and command execution through the MCP bridge. This vulnerability is fixed in 0.4.37.

CVSS v3
10.0
EG Score
10.0(medium)
EG Risk
76(Attend)
EG Risk 76/100SSVC: Attend

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
Severity100% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
3%
EPSS %ILE
88%
KEV
Not listed

Published

May 19, 2026

Last Modified

July 16, 2026

Advisory Details (2)

Auto-updated Sep 4, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github.
github Patch Available🟡 PoC Available

Unauthenticated Remote Code Execution via unprotected MCP custom plugin routes · Advisory · decolua/9router · GitHub

https://github.com/decolua/9router/security/advisories/GHSA-fhh6-4qxv-rpqj
github_commit Patch Available

commit 992f4db4a0d8 (decolua/9router)

Patch available: decolua/9router v0.4.38 (contains commit 992f4db4a0d8)

https://github.com/decolua/9router/commit/992f4db4a0d858bcc86b4786f2abab117a6ccdf8

Vendor Advisories for CVE-2026-46339(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)
npm(1)
PackageVulnerable rangeFixed inDependents
9router—0.4.37—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 5× in last 7d / 35× 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. 2026-09-04 05:06 UTCEPSS rescore
  2. 2026-09-02 14:12 UTCEPSS rescore
  3. 2026-09-01 13:54 UTCEPSS rescore
  4. 2026-08-30 19:17 UTCEPSS rescore
  5. 2026-08-30 01:22 UTCEPSS rescore
  6. 2026-08-28 21:41 UTCEPSS rescore
  7. 2026-08-27 14:25 UTCEPSS rescore
  8. 2026-08-26 14:46 UTCEPSS rescore
  9. 2026-08-25 13:49 UTCEPSS rescore
  10. 2026-08-23 17:00 UTCEG score recompute
  11. 2026-08-23 00:19 UTCEPSS rescore
  12. 2026-08-21 23:49 UTCEPSS rescore
  13. 2026-08-21 23:36 UTCEG score recompute
  14. 2026-08-20 22:55 UTCEPSS rescore
  15. 2026-08-20 19:00 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 16:56 UTCEG score recompute
  20. 2026-08-16 14:56 UTCEPSS rescore
  21. 2026-08-16 03:33 UTCEG score recompute
  22. 2026-08-16 02:14 UTCEPSS rescore
  23. 2026-08-15 01:30 UTCEPSS rescore
  24. 2026-08-14 02:06 UTCEG score recompute
  25. 2026-08-13 22:00 UTCEPSS rescore
Show 42 more
  1. 2026-08-12 15:47 UTCEG score recompute
  2. 2026-08-12 13:51 UTCEPSS rescore
  3. 2026-08-11 13:53 UTCEG score recompute
  4. 2026-08-11 00:38 UTCEG score recompute
  5. 2026-08-11 00:00 UTCEPSS rescore
  6. 2026-08-09 01:35 UTCEG score recompute
  7. 2026-08-08 16:37 UTCEPSS rescore
  8. 2026-08-07 19:33 UTCEG score recompute
  9. 2026-08-06 16:45 UTCEG score recompute
  10. 2026-08-06 13:47 UTCEPSS rescore
  11. 2026-08-05 21:20 UTCEG score recompute
  12. 2026-08-05 19:17 UTCEPSS rescore
  13. 2026-08-04 15:10 UTCEPSS rescore
  14. 2026-08-04 10:39 UTCEPSS rescore
  15. 2026-08-03 16:57 UTCEG score recompute
  16. 2026-08-03 10:36 UTCEPSS rescore
  17. 2026-08-02 05:16 UTCEG score recompute
  18. 2026-08-02 02:27 UTCEPSS rescore
  19. 2026-08-01 17:52 UTCEG score recompute
  20. 2026-08-01 04:16 UTCEPSS rescore
  21. 2026-07-30 16:28 UTCEPSS rescore
  22. 2026-07-30 01:30 UTCEPSS rescore
  23. 2026-07-28 15:36 UTCEPSS rescore
  24. 2026-07-27 14:13 UTCEPSS rescore
  25. 2026-07-26 14:54 UTCEPSS rescore
  26. 2026-07-26 14:54 UTCEPSS rescore
  27. 2026-07-25 14:18 UTCEPSS rescore
  28. 2026-07-24 14:17 UTCEPSS rescore
  29. 2026-07-23 14:18 UTCEPSS rescore
  30. 2026-07-23 03:17 UTCEG score recompute
  31. 2026-07-22 14:08 UTCEPSS rescore
  32. 2026-07-21 15:24 UTCEPSS rescore
  33. 2026-07-20 17:08 UTCEPSS rescore
  34. 2026-07-19 14:31 UTCEPSS rescore
  35. 2026-07-19 02:29 UTCEPSS rescore
  36. 2026-07-18 10:04 UTCEPSS rescore
  37. 2026-07-17 23:29 UTCOSV refresh
  38. 2026-07-16 17:03 UTCEPSS rescore
  39. 2026-06-14 23:18 UTCEPSS rescore
  40. 2026-06-13 23:00 UTCEPSS rescore
  41. 2026-06-12 23:12 UTCEPSS rescore
  42. 2026-05-24 06:13 UTCEG score recompute

Publicly available exploits

(1 reference)

Working exploit code is in the public domain. Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Nucleihttp/cves/2026/CVE-2026-46339.yaml
    First seen Jan 1, 2026

    9Router <= 0.4.36 - Unauthenticated RCE

    Open source ↗

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-46339?
CVE-2026-46339 is a critical vulnerability published on May 19, 2026. 9Router is an AI router & token saver. From 0.4.30 until 0.4.37, 9Router's src/proxy.js middleware did not protect /api/cli-tools/ and /api/mcp/, allowing unauthenticated registration of customPlugins through src/app/api/cli-tools/cowork-settings/route.js and command execution through the MCP…
When was CVE-2026-46339 disclosed?
CVE-2026-46339 was first published in the National Vulnerability Database on May 19, 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-2026-46339 actively exploited?
CVE-2026-46339 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 3% probability of exploitation in the next 30 days, which ranks it in the top 12.1% of all scored CVEs.
What is the CVSS score of CVE-2026-46339?
CVE-2026-46339 has a CVSS v3 base score of 10.0 (NVD).
How do I remediate CVE-2026-46339?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-46339, 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-2026-46339

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