---
id: "CVE-2026-122140"
kind: "vulnerability"
aliases: ["CVE-2026-122140"]
title: "Trawl: MCP URL policy bypass lets attackers reach internal services"
severity: "medium"
cvss: 6.3
epss: null
exploited: false
status: "open"
category: "ai-tooling"
products: []
ecosystems: []
tags: ["ai-tooling", "cloud", "mcp", "trawl"]
not_affected_if: ["no-mcp-url-fetch", "version-1.10.0-or-later"]
published_at: "2026-11-04T21:18:10+00:00"
first_seen_at: "2026-11-04T21:49:21+00:00"
updated_at: "2026-11-04T21:51:12+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-122140", "first_seen_at": "2026-11-04T21:49:21+00:00"}]
exploit_sources: []
---

# Trawl: MCP URL policy bypass lets attackers reach internal services

Trawl versions from 1.5.0 before 1.10.0 check outbound MCP URLs against a block list, but IPv4-mapped IPv6 addresses such as ::ffff:7f00:1 slip past it, including via redirects. An unauthenticated attacker can make the server fetch loopback, private network and cloud metadata endpoints and read the responses.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed Trawl version; affected if it is `1.5.0` up to but not including `1.10.0`.
- Look for MCP URL fetching enabled on servers reachable from untrusted networks.

## Fix

- Move to Trawl `1.10.0` or later.

## Timeline

- 2026-11-04T21:49:21+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-122140

## Documents

- [advisory] Vendor advisory: github.com https://github.com/germondai/trawl/security/advisories/GHSA-mj45-84p2-v77q
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/trawl-1.5.0-before-1.10.0-ssrf-via-ipv4-mapped-ipv6-mcp-policy-bypass
- [fix] Patch: github.com https://github.com/germondai/trawl/commit/17cdb33a9a6a8200cf8f9fd6a57b295b04ee5173
- [fix] Release notes: github.com https://github.com/germondai/trawl/releases/tag/v1.10.0

## From the sources

Trawl 1.5.0 before 1.10.0 contains a server-side request forgery vulnerability that allows unauthenticated attackers to bypass the MCP outbound URL policy using IPv4-mapped IPv6 addresses. Attackers can supply hex-normalized addresses like ::ffff:7f00:1 directly or via redirects to fetch loopback, private, and cloud metadata services and read responses.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_