Hyper-mcp CVEs and Security Vulnerabilities

CVE-2026-108699

hyper-mcp through 0.8.3 Improper Signature Verification of OCI WebAssembly Plugins

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.

CVSS 4.0 · 8.3 High EPSS < 1% KEV · Not listed

Vendors

Hyper-mcp-rs

Products

Hyper-mcp

CVE-2026-108698

hyper-mcp through 0.8.3 OCI Plugin Signature Verification TOCTOU Race Condition

hyper-mcp through 0.8.3 contains a signature verification bypass vulnerability in load_wasm in src/wasm/oci.rs that verifies the Cosign signature of a separately resolved tag rather than the loaded manifest. Attackers controlling registry responses for the tag can serve an unsigned malicious manifest to the loader and a signed one to Cosign, executing unsigned WebAssembly plugins with configured host capabilities.