CVE-2026-63732

critical · 9.4

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.

9.4

CVSS

1.0%

EPSS (exploit prob.)

62nd

EPSS percentile

2026-07-23

Published

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Weaknesses

CWE-78

References

https://github.com/decolua/9router/security/advisories/GHSA-4922-8r65-fq26
https://www.vulncheck.com/advisories/9router-before-remote-code-execution-via-default-password

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-63732