Description
hyper-mcp through 0.8.3 contains an improper signature verification vulnerability that allows attackers to load malicious WebAssembly plugins because cosign_verify_args() accepts any signer identity and OIDC issuer by default. Attackers controlling a plugin image reference can sign a malicious image with a free Sigstore keyless certificate to execute plugins with configured host, filesystem, and environment capabilities.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| hyper-mcp-rs | hyper-mcp | ≤ 0.8.3 | — |
References
- https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/hyper-mcp-oci-signature-manifest-toctou third-party-advisory
- https://github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/wasm/oci.rs#L157-L190 technical-description
- https://github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/config.rs#L138-L170 technical-description
- https://github.com/hyper-mcp-rs/hyper-mcp product
- VulnCheck Advisory: hyper-mcp through 0.8.3 Improper Signature Verification of OCI WebAssembly Plugins third-party-advisory