CVE-2026-44427Public exploitNetwork attack vector

External redirects via unsanitized protocol-relative paths

Published May 14, 2026 · Updated May 14, 2026

Open redirect in MCP Registry 1.1.0 through 1.7.4 allows remote attackers to send users to external sites via crafted URLs. TrailingSlashMiddleware in internal/api/server.go trims a trailing slash and places the unvalidated protocol-relative path into a 308 Location header, which browsers resolve off-host. Exploitation requires a user to follow the crafted registry link; the redirect supports phishing or malicious-download delivery without changing registry data.

CVSS severity0.0
None
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Open redirect in MCP Registry 1.1.0 through 1.7.4 allows remote attackers to send users to external sites via crafted URLs. TrailingSlashMiddleware in internal/api/server.go trims a trailing slash and places the unvalidated protocol-relative path into a 308 Location header, which browsers resolve off-host. Exploitation requires a user to follow the crafted registry link; the redirect supports phishing or malicious-download delivery without changing registry data.

The record

CVE
CVE-2026-44427
Published
May 14, 2026
Updated
May 14, 2026
Vendor
Model Context Protocol
Product
MCP Registry
Classifications
CWE-601, T1566.002
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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=>= 1.1.0, < 1.7.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Model Context Protocol · MCP Registryversion=>= 1.1.0, < 1.7.5

Published CVSS scores

0.0GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:N/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-601URL Redirection to Untrusted Site ('Open Redirect')
T1566.002Spearphishing Link

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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