@jshookmcp/jshook: ICMP probe and traceroute skip local-network SSRF authorization (CVE-2026-49856) | HOL Guard CVE

Medium · CVSS 4.3CVE-2026-49856GHSA-C5R6-M4MR-8Q5J

@jshookmcp/jshook: ICMP probe and traceroute skip local-network SSRF authorization

Answer in brief

CVE-2026-49856 records a Medium severity (CVSS 4.3) vulnerability in @jshookmcp/jshook: ICMP probe and traceroute skip local-network SSRF authorization. The current sources do not mark it as known exploited. The current feed maps vmoranv/jshookmcp (generic), @jshookmcp/jshook (npm). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 13, 2026Updated Aug 13, 2026Source checked Sep 17, 2026First seen by HOL Jul 1, 2026Material review Aug 13, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 4.3
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 4.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps vmoranv/jshookmcp (generic), @jshookmcp/jshook (npm). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
vmoranv/jshookmcpgeneric	= 0.3.1	Not reported
@jshookmcp/jshooknpm	=0.3.1	0.3.2

Recommended response

Check inventory. Check lockfiles and deployed manifests for vmoranv/jshookmcp, @jshookmcp/jshook.
Review the reported fix. Update @jshookmcp/jshook to 0.3.2 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 13, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 13, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Jul 1, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.