Server-Side Request Forgery in jshookmcp by vmoRanV
CVE-2026-49856

4.3MEDIUM

Key Information:

Vendor

Vmoranv

Status
Jshookmcp
Vendor
CVE Published:
13 August 2026

What is CVE-2026-49856?

The jshookmcp server, utilized for JavaScript analysis and security research, contains a server-side request forgery vulnerability in version 0.3.1. The server's authorization policy restricts access to private, loopback, link-local, and reserved targets. However, this can be bypassed using specific MCP client methods to probe internal addresses, thereby exposing sensitive internal network information. This flaw allows unauthorized access to internal network details, which can be exploited if proper security measures are not in place. The issue was resolved in version 0.3.2.

Affected Version(s)

jshookmcp = 0.3.1

References

https://github.com/vmoranv/jshookmcp/security/advisories/...
x_refsource_CONFIRM
https://github.com/vmoranv/jshookmcp/commit/02111311f7bd0...
x_refsource_MISC

CVSS V3.1

Score:
4.3
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
None
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.