{"id":"CVE-2026-108699","aliases":["EUVD-2026-96999","GHSA-4j25-h357-wg62"],"status":"published","title":"hyper-mcp through 0.8.3 Improper Signature Verification of OCI WebAssembly Plugins","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.","severity":{"version":"4.0","score":8.3,"vector":"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","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00169,"percentile":0.06294,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-347"],"published":"2026-10-11T13:25:59Z","modified":"2026-10-28T02:30:25Z","products":[{"vendor":"hyper-mcp-rs","product":"hyper-mcp"}],"references":[{"url":"https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/hyper-mcp-oci-signature-manifest-toctou","tags":["third-party-advisory","advisory"]},{"url":"https://github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/wasm/oci.rs#L157-L190","tags":["technical-description","article"]},{"url":"https://github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/config.rs#L138-L170","tags":["technical-description","article"]},{"url":"https://github.com/hyper-mcp-rs/hyper-mcp","tags":["product","package"]},{"url":"https://www.vulncheck.com/advisories/hyper-mcp-through-0.8.3-improper-signature-verification-of-oci-webassembly-plugins","tags":["third-party-advisory","advisory"]},{"url":"https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/cve-2026-108698-108699-hyper-mcp-oci-signature-manifest-toctou","tags":["exploit","evidence"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-108699","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-4j25-h357-wg62"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/108xxx/CVE-2026-108699.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-108699","title":"hyper-mcp through 0.8.3 Improper Signature Verification of OCI WebAssembly Plugins","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.","status":"published","published":"2026-10-11T13:25:59.469Z","modified":"2026-10-13T19:35:43.889Z","cvss":[{"version":"4.0","score":8.3,"vector":"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","level":"high","assessor":"cna"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T14:20:10.510075Z"}],"euvd":[{"id":"EUVD-2026-96999","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.","status":"published","published":"2026-10-11T13:25:59Z","modified":"2026-10-13T19:35:43Z","cvss":[{"version":"4.0","score":8.3,"vector":"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","level":"high"}],"updated_at":"2026-11-02T17:27:18.769576Z"}],"ghsa":[{"id":"GHSA-4j25-h357-wg62","title":"hyper-mcp through 0.8.3 contains an improper signature verification vulnerability that allows...","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.","status":"published","published":"2026-10-11T15:31:06Z","modified":"2026-10-13T21:32:16Z","cvss":[{"version":"4.0","score":8.3,"vector":"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","level":"medium"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T15:13:12.080152Z"}],"nvd":[{"id":"CVE-2026-108699","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.","status":"published","published":"2026-10-11T14:17:04.257Z","modified":"2026-10-16T19:21:14.417Z","cvss":[{"version":"4.0","score":8.3,"vector":"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T14:12:55.874869Z"}],"osv":[{"id":"CVE-2026-108699","title":"hyper-mcp through 0.8.3 Improper Signature Verification of OCI WebAssembly Plugins","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.","status":"published","published":"2026-10-11T13:25:59.469Z","modified":"2026-10-28T02:30:25.385173482Z","cvss":[{"version":"4.0","score":8.3,"vector":"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","level":"high"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T15:44:55.279797Z"}]}}