Record summary

CVE-2026-49856 has a selected CVSS score of 4.3 (medium).

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.

Description source: CVE List

Exploitation context

CISA SSVC decision

ExploitationPoC
AutomatableNo
Technical impactPartial

CISA Coordinator · SSVC 2.0.3 · Evaluated Aug 13, 2026 · Source: CVE List

Affected products and versions

2
ProductSourceVersion rangeStatus
CVE List= 0.3.1affected
GitHub Advisory0.3.1affected
0.3.1 to < 0.3.2 · Fixed in 0.3.2affected

References

3