{"id":"CVE-2026-45781","summary":"MCP Registry: OCI ownership validation fails open on upstream rate limits, allowing attacker-controlled package claims","details":"The MCP Registry provides MCP clients with a list of MCP servers, like an app store for MCP servers. Prior to 1.7.9, OCI ownership validation skips label-match check when upstream OCI registry returns HTTP 429, letting any authenticated publisher bind their io.github.\u003cuser\u003e/* namespace to OCI images they do not control. internal/validators/registries/oci.go:104-119 fails open on http.StatusTooManyRequests: when the registry's anonymous fetch to the upstream OCI registry is rate-limited, ValidateOCI returns nil and the publish is accepted without ever running the io.modelcontextprotocol.server.name label-match check at lines 122-141. That label check is the only cross-system ownership proof the registry applies to OCI packages — every other registry type (NPM, PyPI, NuGet, MCPB) treats a non-200 upstream response as a hard error. This vulnerability is fixed in 1.7.9.","aliases":["GHSA-2v5f-5r6w-p67r","GO-2026-5008"],"modified":"2026-07-08T08:13:31.464555365Z","published":"2026-05-14T21:00:49.961Z","related":["CGA-2px9-j47v-c48r"],"database_specific":{"cwe_ids":["CWE-636"],"cna_assigner":"GitHub_M","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45781.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45781.json"},{"type":"ADVISORY","url":"https://github.com/modelcontextprotocol/registry/security/advisories/GHSA-2v5f-5r6w-p67r"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-45781"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/modelcontextprotocol/registry","events":[{"introduced":"0"},{"fixed":"35b20719ee7714ad18d0f81af6798ac0a46e2b9b"}],"database_specific":{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"0"},{"fixed":"1.7.9"}]}}],"versions":["v1.7.8","v1.7.7","v1.7.6","v1.7.5","v1.7.4","v1.7.3","v1.7.2","v1.7.1","v1.7.0","v1.6.0","v1.5.0","v1.4.1","v1.4.0","v1.3.10","v1.3.9","v1.3.8","v1.3.7","v1.3.6","v1.3.5","v1.3.4","v1.3.3","v1.3.2","v1.3.1","v1.3.0","v1.2.3","v1.2.2","v1.2.1","v1.2.0","v1.1.0","v1.0.0","v0.0.3","v0.0.2","v0.0.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-45781.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N"}]}