TI-2026-33518 Aliases CVE-2026-45781 GHSA-2v5f-5r6w-p67r

MCP Registry: OCI ownership validation fails open on upstream rate limits, allowing attacker-controlled package claims

MEDIUM 50CWE-636Published 2026-05-14 · Updated 2026-05-16

Key facts

Attack vector: Network
Privileges required: Low
User interaction: Required
Attack complexity: Low
Impact type: —
Confidentiality · integrity · availability: None · Low · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00233 14th percentileScored 2026-11-07

Fix Fixed registry (modelcontextprotocol): 1.7.9github.com/modelcontextprotocol/registry (Go): 1.7.9

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
MLflow	registry	before 1.7.9	1.7.9	Patch available	CNA
—	github.com/modelcontextprotocol/registry (Go)	before 1.7.9	1.7.9	Patch available	GHSA-2v5f-5r6w-p67r

registry VendorMLflow Affected before 1.7.9 Fixed in 1.7.9 Patch available CNA
github.com/modelcontextprotocol/registry (Go) Vendor— Affected before 1.7.9 Fixed in 1.7.9 Patch available GHSA-2v5f-5r6w-p67r

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:lfprojects:mcp_registry::::::::	—	—	MLflow

cpe:2.3:a:lfprojects:mcp_registry:*:*:*:*:*:*:*:* Versions — — ·MLflow

Remediation

Fix · CNA registry (modelcontextprotocol) Fixed in 1.7.9
Fix · GHSA-2v5f-5r6w-p67r github.com/modelcontextprotocol/registry (Go) Fixed in 1.7.9 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-45781
2026-10-03 Alias added: GHSA-2v5f-5r6w-p67r

References

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-45781

Other 2

TI-2026-46366 Server-side request forgery in mlflow KEVCVSS 3.1CRITICAL 9.3
TI-2023-03518 Absolute Path Traversal in mlflow/mlflow CVSS 3.1CRITICAL 10.0
TI-2023-01113 Path Traversal: '\..\filename' in mlflow/mlflow CVSS 3.1CRITICAL 9.8
TI-2025-31759 Redis Lua Use-After-Free may lead to remote code execution CVSS 3.1CRITICAL 10.0
TI-2026-81527 Code execution via scorer deserialization in MLflow servers CVSS 3.1CRITICAL 9.8
TI-2025-14028 Command Injection in mlflow/mlflow CVSS 3.1CRITICAL 10.0

See all 175 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences