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.
CVE-2026-46339
CRITICALPre-NVD 10.010.0Elevated
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
10.0
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 5%CVSS: 10.0Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 10.0
- EG Score
- 10.0(low)
- EG Risk
- —
- EPSS
- 90.6%
- 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-rpqjgithub_commit Patch Available
commit 992f4db4a0d8 (decolua/9router)
Patch available: decolua/9router v0.4.38 (contains commit 992f4db4a0d8)
https://github.com/decolua/9router/commit/992f4db4a0d858bcc86b4786f2abab117a6ccdf8Vendor 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)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| 9router | — | 0.4.37 | — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 8× in last 7d / 8× 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.
- 2026-07-22 14:08 UTCEPSS rescore
- 2026-07-21 15:24 UTCEPSS rescore
- 2026-07-20 17:08 UTCEPSS rescore
- 2026-07-19 14:31 UTCEPSS rescore
- 2026-07-19 02:29 UTCEPSS rescore
- 2026-07-18 10:04 UTCEPSS rescore
- 2026-07-17 23:29 UTCOSV refresh
- 2026-07-16 17:03 UTCEPSS rescore
- 2026-06-14 23:18 UTCEPSS rescore
- 2026-06-13 23:00 UTCEPSS rescore
- 2026-06-12 23:12 UTCEPSS rescore
- 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.yamlFirst seen Jan 1, 2026
9Router <= 0.4.36 - Unauthenticated RCE
Open source ↗
Related CVEs(same CWE)
Same CWE
10 shownCWE-78 · CWE-306
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- CVE-2010-5326EG 10.0 KEVEPSS 97%CRITICAL
- CVE-2011-10026EG 9.8CRITICAL
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- CVE-2011-2195EG 9.8CRITICAL
- CVE-2011-2523EG 9.8EPSS 100%CRITICAL
- CVE-2006-0062EG 9.8CRITICAL
- CVE-2006-0061EG 9.8CRITICAL
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 90.6% 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
Is Your Infrastructure Affected by CVE-2026-46339?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.