CVE-2026-45781Public exploitNetwork attack vector

Authenticated package claims via rate-limit fail-open

Published May 14, 2026 · Updated May 14, 2026

Authorization bypass in Model Context Protocol MCP Registry before 1.7.9 allows remote authenticated users to claim unrelated OCI images. The ValidateOCI path returns success on an upstream HTTP 429 before comparing the image io.modelcontextprotocol.server.name label with the submitted server name. A GitHub-authenticated publisher can exhaust the shared anonymous pull quota and bind an unrelated public image to a record in that publisher's namespace, enabling impersonation without changing the image.

CVSS severity3.5
Low
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authorization bypass in Model Context Protocol MCP Registry before 1.7.9 allows remote authenticated users to claim unrelated OCI images. The ValidateOCI path returns success on an upstream HTTP 429 before comparing the image io.modelcontextprotocol.server.name label with the submitted server name. A GitHub-authenticated publisher can exhaust the shared anonymous pull quota and bind an unrelated public image to a record in that publisher's namespace, enabling impersonation without changing the image.

The record

CVE
CVE-2026-45781
Published
May 14, 2026
Updated
May 14, 2026
Vendor
Model Context Protocol
Product
MCP Registry
Classifications
CWE-636
Attack vector
network
Privileges
authenticated

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=< 1.7.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Model Context Protocol · MCP Registryversion=< 1.7.9

Published CVSS scores

3.5GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A: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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-636Not Failing Securely ('Failing Open')

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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