RCE in Decolua 9router
CVE-2026-63732
9router 0.4.59 (fixed in 0.4.60) contains a chain of vulnerabilities: a hardcoded default password (123456) that authenticates any fresh installation, a bypass of the LOCAL_ONLY network gate via a spoofed Host header, and unvalidated arguments passed to child_process.spawn() when registering MCP plugins. A remote, unauthenticated attacker can log in with the default credential, spoof the Host header to reach local-only routes, and register a malicious MCP plugin (e.g. node -e <payload>) to achieve arbitrary code execution on the host operating system when the plugin's SSE endpoint is triggered.
Vulnerability class: Command Injection (OS Command Injection)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.010 (62.9th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 63rd percentile — 62.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000
Affected products
- Decolua 9router — versions 0, 0.4.60
Weakness classification (CWE)
References
- github.com/decolua/9router/security/advisories/GHSA-4922-8r65-fq26 (vendor-advisory)
- www.vulncheck.com/advisories/9router-before-remote-code-execution-via-default-p… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-63732?
- CVE-2026-63732 is a critical-severity vulnerability in Decolua 9router, classified under OS Command Injection. CVSS score: 9.9/10. Published 2026-07-23.
- How severe is CVE-2026-63732?
- Critical severity. CVSS v3 base score is 9.9 out of 10.