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CVE-2026-44428

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

Description (CNA)

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 (CNA)

Vendor / productVersions
modelcontextprotocol / registryaffected < 1.7.6

CWE

CWE-918

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.