[SECURITY] Status of DNS Rebinding Vulnerability Fix for rust-sdk

[JLLeitschuh]

I found (and reported to Anthropic here) that all major MCP Server SDKs were vulnerable to browser-based DNS rebinding allowing malicious websites to talk to locally or private network connected MCP servers.

This is was in violation of the MCP specification : https://modelcontextprotocol.io/specification/2025-06-18/basic/transports#security-warning

This resulted in a slew of CVEs assigned to every major SDK:

• GHSA-w48q-cv73-mx4w
• GHSA-9h52-p55h-vw2f
• GHSA-xw59-hvm2-8pj6
• GHSA-8jxr-pr72-r468

It's not clear to me what version, if it was at all, of the rust-sdk this was fixed in, as no CVE was assigned. Would the project maintainers behind this project be so kind as to do create a GitHub Security Advisory and request a CVE including the fix version and credit myself?

Thanks team!

[JLLeitschuh]

See also: modelcontextprotocol/csharp-sdk#1520

[DaleSeo]

Hi @JLLeitschuh — thanks for the report and the follow-up.

I believe the fix already landed in PR #764 and was first released in v1.4.0 on 2026-04-09.

@alexhancock Do you want me to file a GitHub Security Advisory? I've never done it before but I can give it a try 😅

[JLLeitschuh]

Let me know if you have any issues. Getting a CVE number is the best way to signal to your downstream users that this vulnerability was present and that they need to update their SDK version to adequately fix the issue. Without a CVE number, end-users are unlikely to update quickly

[DaleSeo]

@JLLeitschuh @alexhancock The GitHub Security Advisory is drafted at https://github.com/modelcontextprotocol/rust-sdk/security/advisories/GHSA-89vp-x53w-74fx. If you want any wording changed, the draft is editable, or leave comments here and I'll fold them in before publishing.