CVE-2026-45781: MCP Registry: OCI ownership validation fails open on upstream rate limits, allowing attacker-controlled package claims
modelcontextprotocol · registry
Affected: modelcontextprotocol registry · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 14% of scored CVEs
DescriptionCVE.org
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.<user>/* 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.
Affected products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- modelcontextprotocol · registry< 1.7.9
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Vendor
- modelcontextprotocol
- Published
- May 2026
CoverageNo articles yet
No CyberSIXT article names CVE-2026-45781 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.