---
id: CVE-2026-81100
title: >-
  tiger-gh-mcp-server started its MCP HTTP transport without enabling the host
  allow-list the underlying SDK provides
summary: >-
  tiger-gh-mcp-server started its MCP HTTP transport without enabling the host
  allow-list the underlying SDK provides. src/httpServer.ts called the shared
  httpServerFactory helper and never set the DNS-rebinding-protection option, so
  the t…
severity: medium
cvss: 6.8
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N'
cwe:
  - CWE-346
published: '2026-08-27'
updated: '2026-09-23'
sourceUpdated: '2026-09-23T17:17:43.453'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-81100'
references:
  - url: 'https://github.com/timescale/tiger-gh-mcp-server'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/timescale/tiger-gh-mcp-server/pull/36'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/timescale-tiger-gh-mcp-server-dns-rebinding-via-disabled-host-header-allow-list
    label: disclosure@vulncheck.com
tags:
  - nvd
epss: 0.00216
epssPercentile: 0.10821
ingestedAt: '2026-08-29T21:42:35.239Z'
---

## Overview

tiger-gh-mcp-server started its MCP HTTP transport without enabling the host allow-list the underlying SDK provides. src/httpServer.ts called the shared httpServerFactory helper and never set the DNS-rebinding-protection option, so the transport accepted a request whatever host it named, making the locally reachable GitHub MCP endpoint drivable from a page in a visitor's browser that pointed a name it controlled at the bound address. The fix passes the option explicitly alongside a dependency update; the update alone would not have closed it. The repository has published no release that brackets the fix, so the affected boundary is the commit preceding it.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.