CVE-2026-108699CWE-347

CVE-2026-108699

Medium · published October 11, 2026

CVSS v3.1
6.5
EPSS
0%
Percentile
2.6
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N
CVSS v4.0
8.3 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N
EPSS
0.00134 · 2.6th percentile
Weakness
CWE-347 · Improper Verification of Cryptographic Signature
Published
2026-10-11T18:17Z
References (6)
https://github.com/hyper-mcp-rs/hyper-mcp · [email protected]https://github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/config.rs#L138-L170 · [email protected]https://github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/wasm/oci.rs#L157-L190 · [email protected]https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/hyper-mcp-oci-signature-manifest-toctou · [email protected]https://www.vulncheck.com/advisories/hyper-mcp-through-0.8.3-improper-signature-verification-of-oci-webassembly-plugins · [email protected]https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/cve-2026-108698-108699-hyper-mcp-oci-signature-manifest-toctou · 134c704f-9b21-4f2e-91b3-4a467353bcc0
EPSS history
Timeline
  • 13 OCT 03:28Z
    EPSS moved — → 0%
    epss
  • 11 OCT 13:25Z
    hyper-mcp through 0.8.3 Improper Signature Verification of OCI WebAssembly Plugins
    cvelistv5
  • 11 OCT 13:25Z
    hyper-mcp through 0.8.3 Improper Signature Verification of OCI WebAssembly Plugins
    cvelistv5