CVE-2026-49856 — MEDIUM (4.3)

Vulnerability Description

@jshookmcp/jshook is an MCP server that gives AI agents tools for JavaScript analysis and security research. In version 0.3.1, he network domain has a central SSRF authorization policy that blocks private, loopback, link-local, and reserved targets unless an explicit authorization object allows private network access. The policy is enforced by raw HTTP/TCP/TLS RTT tools, but the ICMP probe and traceroute tools resolve the target and invoke the native ICMP/traceroute sink directly. An MCP client with access to an active network domain can therefore ask the jshookmcp server to probe internal addresses even when local SSRF access is disabled for the other raw network tools. This exposes an internal reachability and route mapping primitive from the server network position. Version 0.3.2 fixes the issue.

CVSS Score

4.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

LOW

Integrity

NONE

Availability

NONE

Related Weaknesses (CWE)

CWE-918

References

FAQ

What is CVE-2026-49856?

CVE-2026-49856 is a vulnerability with a CVSS score of 4.3 (MEDIUM). @jshookmcp/jshook is an MCP server that gives AI agents tools for JavaScript analysis and security research. In version 0.3.1, he network domain has a central SSRF authorization policy that blocks pri...

How severe is CVE-2026-49856?

CVE-2026-49856 has been rated MEDIUM with a CVSS base score of 4.3/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-49856?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.