Is CVE-2026-44430 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-44430 being exploited in the wild.

How severe is CVE-2026-44430?

Medium severity, with a CVSS score of 4, published 14 May 2026.

Which products and versions are affected?

github.com/modelcontextprotocol/registry (Go) < 1.7.7, SEMVER:introduced=0,fixed=1.7.7; Model Context Protocol MCP Registry < 1.7.7; Model Context Protocol Registry < 1.7.7.

Is there a fix for CVE-2026-44430?

Yes. github.com/modelcontextprotocol/registry (Go): upgrade to 1.7.7 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-44430 attacked?

It is attacked over the network, in a hosted service.

Am I affected by CVE-2026-44430?

Check whether you run github.com/modelcontextprotocol/registry (Go), Model Context Protocol MCP Registry or Model Context Protocol Registry at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-44430: Model Context Protocol Registry SSRF via IPv6 Filter Bypass

Q: Is there a fix for CVE-2026-44430?

Yes. github.com/modelcontextprotocol/registry (Go): upgrade to 1.7.7 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-44430 attacked?

It is attacked over the network, in a hosted service.

Q: Am I affected by CVE-2026-44430?

Check whether you run github.com/modelcontextprotocol/registry (Go), Model Context Protocol MCP Registry or Model Context Protocol Registry at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-44430 · Severity: medium · CVSS 4 · Published 2026-05-14

The Model Context Protocol (MCP) Registry, a service used for managing and verifying namespaces, contains a security flaw in how it validates server addresses. An unauthenticated attacker can trick the registry into making network requests to internal infrastructure, such as cloud metadata services or private databases, by using specific IPv6 address formats. This could lead to the exposure of sensitive internal configuration data or credentials, potentially compromising the security of the hosting environment.

Technologies: github.com/modelcontextprotocol/registry (Go), Model Context Protocol Registry. Vendors: Go, Model Context Protocol.

Quick answers

Is CVE-2026-44430 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-44430 being exploited in the wild.
How severe is CVE-2026-44430?: Medium severity, with a CVSS score of 4, published 14 May 2026.
Which products and versions are affected?: github.com/modelcontextprotocol/registry (Go) < 1.7.7, SEMVER:introduced=0,fixed=1.7.7; Model Context Protocol MCP Registry < 1.7.7; Model Context Protocol Registry < 1.7.7.
Is there a fix for CVE-2026-44430?: Yes. github.com/modelcontextprotocol/registry (Go): upgrade to 1.7.7 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-44430 attacked?: It is attacked over the network, in a hosted service.
Am I affected by CVE-2026-44430?: Check whether you run github.com/modelcontextprotocol/registry (Go), Model Context Protocol MCP Registry or Model Context Protocol Registry at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

github.com/modelcontextprotocol/registry (Go): upgrade to 1.7.7 or later
```
go get github.com/modelcontextprotocol/registry@v1.7.7
```

Technical details

A Server-Side Request Forgery (SSRF) exists in the `POST /v0/auth/http` and `POST /v0.1/auth/http` endpoints of the MCP Registry. The `isBlockedIP` function in `internal/api/handlers/v0/auth/http.go` relies on standard Go library helpers that do not filter IPv6 prefixes used for embedding IPv4 addresses, specifically 6to4 (2002::/16), NAT64 (64:ff9b::/96), and deprecated site-local (fec0::/10) addresses. An unauthenticated attacker can provide a domain resolving to these prefixes to bypass the private-address allowlist and reach internal RFC1918 or cloud metadata services (e.g., 169.254.169.254) on dual-stack or NAT64-enabled hosts. The vulnerability is exploitable because the network dial occurs before signature verification. The issue is patched in version 1.7.7.

Affected products

modelcontextprotocol registry < 1.7.7

Identifiers

CVE-2026-44430
GHSA-r48c-v28r-pf6v
GO-2026-5607

Timeline

2026-05-04: advisory: GitHub Advisory GHSA-r48c-v28r-pf6v published
2026-05-08: disclosed
2026-05-15: patched: Version 1.7.7 released

References

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