CVE-2026-45781: CWE-636: Not Failing Securely ('Failing Open') in modelcontextprotocol registry
CVE-2026-45781 is a vulnerability in the modelcontextprotocol (MCP) registry prior to version 1.7.9. The issue arises because the OCI ownership validation fails open when the upstream OCI registry returns an HTTP 429 (Too Many Requests) response. This failure allows any authenticated publisher to bind namespaces they do not control to OCI images, bypassing the critical label-match ownership check. The vulnerability is specific to OCI packages; other package types enforce stricter validation. This flaw has a low severity score and no known exploits in the wild. A fix was introduced in version 1.7.9.
AI Analysis
Technical Summary
The MCP Registry provides clients with a list of MCP servers and validates ownership of OCI images by checking a label-match in the upstream OCI registry. Before version 1.7.9, when the upstream OCI registry rate-limits requests (HTTP 429), the validation function ValidateOCI incorrectly returns success without performing the label-match check. This 'fail open' behavior (CWE-636) allows authenticated publishers to bind namespaces they do not own, compromising ownership integrity for OCI packages. Other package types treat non-200 responses as errors, preventing this bypass. The vulnerability is fixed in MCP Registry version 1.7.9.
Potential Impact
The vulnerability allows authenticated publishers to bypass ownership validation for OCI images under certain rate-limiting conditions, potentially enabling unauthorized namespace binding. This could lead to integrity issues in the MCP Registry's handling of OCI packages. The impact is limited to integrity (no confidentiality or availability impact) and is rated low severity with a CVSS score of 3.5. There are no known exploits in the wild.
Mitigation Recommendations
Upgrade the MCP Registry to version 1.7.9 or later, where this vulnerability is fixed. Prior to upgrading, be aware that the registry fails open on HTTP 429 responses from the upstream OCI registry, allowing ownership validation bypass. No other mitigations are documented. Patch status is not explicitly stated but the fix is included in version 1.7.9.
CVE-2026-45781: CWE-636: Not Failing Securely ('Failing Open') in modelcontextprotocol registry
Description
CVE-2026-45781 is a vulnerability in the modelcontextprotocol (MCP) registry prior to version 1.7.9. The issue arises because the OCI ownership validation fails open when the upstream OCI registry returns an HTTP 429 (Too Many Requests) response. This failure allows any authenticated publisher to bind namespaces they do not control to OCI images, bypassing the critical label-match ownership check. The vulnerability is specific to OCI packages; other package types enforce stricter validation. This flaw has a low severity score and no known exploits in the wild. A fix was introduced in version 1.7.9.
CVSS v3.1
Score 3.5low
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The MCP Registry provides clients with a list of MCP servers and validates ownership of OCI images by checking a label-match in the upstream OCI registry. Before version 1.7.9, when the upstream OCI registry rate-limits requests (HTTP 429), the validation function ValidateOCI incorrectly returns success without performing the label-match check. This 'fail open' behavior (CWE-636) allows authenticated publishers to bind namespaces they do not own, compromising ownership integrity for OCI packages. Other package types treat non-200 responses as errors, preventing this bypass. The vulnerability is fixed in MCP Registry version 1.7.9.
Potential Impact
The vulnerability allows authenticated publishers to bypass ownership validation for OCI images under certain rate-limiting conditions, potentially enabling unauthorized namespace binding. This could lead to integrity issues in the MCP Registry's handling of OCI packages. The impact is limited to integrity (no confidentiality or availability impact) and is rated low severity with a CVSS score of 3.5. There are no known exploits in the wild.
Mitigation Recommendations
Upgrade the MCP Registry to version 1.7.9 or later, where this vulnerability is fixed. Prior to upgrading, be aware that the registry fails open on HTTP 429 responses from the upstream OCI registry, allowing ownership validation bypass. No other mitigations are documented. Patch status is not explicitly stated but the fix is included in version 1.7.9.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-05-13T07:45:21.252Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a063d1aec166c07b013014d
Added to database: 5/14/2026, 9:22:34 PM
Last enriched: 5/22/2026, 3:31:36 PM
Last updated: 6/18/2026, 5:14:10 AM
Views: 93
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