GHSA-w48q-cv73-mx4w

Suggest an improvement
Source
https://github.com/advisories/GHSA-w48q-cv73-mx4w
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/12/GHSA-w48q-cv73-mx4w/GHSA-w48q-cv73-mx4w.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-w48q-cv73-mx4w
Aliases
Downstream
Published
2025-12-02T16:51:57Z
Modified
2025-12-02T21:59:41.711608Z
Severity
  • 7.6 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N CVSS Calculator
Summary
Model Context Protocol (MCP) TypeScript SDK does not enable DNS rebinding protection by default
Details

The Model Context Protocol (MCP) TypeScript SDK does not enable DNS rebinding protection by default for HTTP-based servers. When an HTTP-based MCP server is run on localhost without authentication with StreamableHTTPServerTransport or SSEServerTransport and has not enabled enableDnsRebindingProtection, a malicious website could exploit DNS rebinding to bypass same-origin policy restrictions and send requests to the local MCP server. This could allow an attacker to invoke tools or access resources exposed by the MCP server on behalf of the user in those limited circumstances.

Note that running HTTP-based MCP servers locally without authentication is not recommended per MCP security best practices. This issue does not affect servers using stdio transport.

Servers created via createMcpExpressApp() now have this protection enabled by default when binding to localhost. Users with custom Express configurations are advised to update to version 1.24.0 and apply the exported hostHeaderValidation() middleware when running an unauthenticated server on localhost.

Database specific 
{
    "severity": "HIGH",
    "cwe_ids": [
        "CWE-1188",
        "CWE-350"
    ],
    "github_reviewed_at": "2025-12-02T16:51:57Z",
    "nvd_published_at": "2025-12-02T19:15:52Z",
    "github_reviewed": true
}
References

Affected packages

npm / @modelcontextprotocol/sdk

Package

Name
@modelcontextprotocol/sdk
View open source insights on deps.dev
Purl
pkg:npm/%40modelcontextprotocol/sdk

Affected ranges

Type
SEMVER
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1.24.0