CVE-2026-44430Public exploitNetwork attack vector

Unauthenticated SSRF via incomplete IPv6 address blocklist

Published May 14, 2026 · Updated May 14, 2026

Server-side request forgery in MCP Registry before 1.7.7 allows remote attackers to probe internal HTTPS services through namespace verification. The safeDialContext blocklist omits 6to4, NAT64, and site-local IPv6 prefixes, so publisher-controlled domains can resolve to addresses routing to private IPv4 targets. The unauthenticated endpoints dial before signature verification; exploitation requires compatible IPv6 routing and exposes a blind reachability oracle with responses capped at 4 KiB.

CVSS severity6.3
Medium
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Server-side request forgery in MCP Registry before 1.7.7 allows remote attackers to probe internal HTTPS services through namespace verification. The safeDialContext blocklist omits 6to4, NAT64, and site-local IPv6 prefixes, so publisher-controlled domains can resolve to addresses routing to private IPv4 targets. The unauthenticated endpoints dial before signature verification; exploitation requires compatible IPv6 routing and exposes a blind reachability oracle with responses capped at 4 KiB.

The record

CVE
CVE-2026-44430
Published
May 14, 2026
Updated
May 14, 2026
Vendor
Model Context Protocol
Product
MCP Registry
Classifications
CWE-918, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 14, 2026CVE publishedPublication date reported by the CVE source.
  2. May 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.7.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Model Context Protocol · MCP Registryversion=< 1.7.7

Published CVSS scores

4.0NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
6.3GitHubCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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