CVE-2026-44428

MCP Registry: GitHub OIDC tokens replayable across registry deployments due to shared audience

MEDIUM
4.7
CVSS Score
Published: May 14, 2026 at 09:09 PM UTC
Updated: October 26, 2026 at 02:10 PM UTC
2 products affected across 2 vendorsMcp RegistryMCP Registry

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Severity
MEDIUM4.7
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

Description

The MCP Registry provides MCP clients with a list of MCP servers, like an app store for MCP servers. Prior to 1.7.6, the client-side and server-side GitHub OIDC flow is bound only to a global audience string, not to the specific registry instance being targeted. On the client side, the publisher always appends audience=mcp-registry when requesting the GitHub Actions ID token, regardless of the selected --registry URL. On the server side, the exchange endpoint validates only that same fixed audience and then derives publish permissions directly from repository_owner. As a result, a token legitimately obtained while interacting with one registry deployment remains acceptable to any other deployment that shares the same code and audience string. This vulnerability is fixed in 1.7.6.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.7.6
Affected range stops below 1.7.6, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

x_refsource_CONFIRMMitigationVendor Advisory
Source: cverecord
https://github.com/modelcontextprotocol/registry/security/advisories/GHSA-95c3-6vvw-4mrq

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-918

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