Vulnerability in Hyper-Mcp-Rs Hyper-Mcp
CVE-2026-108699
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.
Published .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/hyper-mcp-oci-signature-manifest-toctou (third-party-advisory)
- github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/wasm/oci.rs (technical-description)
- github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/config.rs (technical-description)
- github.com/hyper-mcp-rs/hyper-mcp (product)
- www.vulncheck.com/advisories/hyper-mcp-through-0.8.3-improper-signature-verific… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-108699?
- CVE-2026-108699 is a medium-severity vulnerability in Hyper-Mcp-Rs Hyper-Mcp, classified under Improper Verification of Cryptographic Signature. CVSS score: 6.5/10. Published 2026-10-11.
- How severe is CVE-2026-108699?
- Medium severity. CVSS v3 base score is 6.5 out of 10.