CVE-2026-46339

CRITICALPre-NVD 10.010.0
EchelonGraph scoreLOW confidence

This critical-severity CVE scores 10.0 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 65% 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
10.0
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 10.0Exploit: NoneExposed: 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(low)
EPSS
35.2%
KEV
Not listed

Published

May 19, 2026

Last Modified

July 16, 2026

Advisory Details (2)

Auto-updated Jul 16, 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 0× in last 7d / 21× 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 120 total refreshes for this CVE.

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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 35.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-46339?
CVE-2026-46339 has a CVSS v3 base score of 10.0 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
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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