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

{
  "id": "091c59849c665c54795eacc8b8386db9ad6003bd76d8f9a8f819112dbea195f8",
  "url": "https://osv.dev/vulnerability/CVE-2026-108699",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "hyper-mcp through 0.8.3 Improper Signature Verification of OCI WebAssembly Plugins",
    "summary": "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.",
    "evidence": "osv:CVE-2026-108699",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-108699",
      "aliases": [
        "CVE-2026-108699"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "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"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/hyper-mcp-rs/hyper-mcp",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "08353e866c53ff072af932bd977180596a3746f3"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "0.8.3"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "0.8.3"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.8.3",
            "v0.8.2",
            "v0.8.1",
            "v0.8.0",
            "v0.7.4",
            "v0.7.3",
            "v0.7.2",
            "v0.7.1",
            "v0.7.0",
            "v0.6.1",
            "v0.6.0",
            "v0.5.6",
            "v0.5.5",
            "v0.5.4",
            "v0.5.3",
            "v0.5.2",
            "v0.5.1",
            "v0.5.0",
            "v0.4.7",
            "v0.4.6",
            "v0.4.5",
            "v0.4.4",
            "v0.4.3",
            "v0.4.2",
            "v0.4.0",
            "v0.3.1",
            "v0.3.0",
            "v0.2.3",
            "v0.2.2",
            "v0.2.1",
            "v0.2.0",
            "v0.1.8",
            "v0.1.7",
            "v0.1.6",
            "v0.1.5",
            "v0.1.4",
            "v0.1.3",
            "v0.1.2",
            "v0.1.1",
            "v0.1.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-108699.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:25.385173482Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/108xxx/CVE-2026-108699.json",
        "https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/hyper-mcp-oci-signature-manifest-toctou",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-108699",
        "https://www.vulncheck.com/advisories/hyper-mcp-through-0.8.3-improper-signature-verification-of-oci-webassembly-plugins",
        "https://github.com/hyper-mcp-rs/hyper-mcp",
        "https://github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/config.rs#L138-L170",
        "https://github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/wasm/oci.rs#L157-L190",
        "https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/cve-2026-108698-108699-hyper-mcp-oci-signature-manifest-toctou"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-347"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/108xxx/CVE-2026-108699.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-108699",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 492119,
  "published_at": "2026-10-11T13:25:59.469+00:00"
}