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.

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact High

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation poc

Automatable no

Technical Impact partial

Affected Vendors & Products

Vendors Products
Hyper-mcp-rs
  • Hyper-mcp

No data.

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References
Link Providers
https://github.com/hyper-mcp-rs/hyper-mcp cve-icon cve-icon
https://github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/config.rs#L138-L170 cve-icon cve-icon
https://github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/wasm/oci.rs#L157-L190 cve-icon cve-icon
https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/cve-2026-108698-108699-hyper-mcp-oci-signature-manifest-toctou cve-icon cve-icon
https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/hyper-mcp-oci-signature-manifest-toctou cve-icon cve-icon
https://www.vulncheck.com/advisories/hyper-mcp-through-0.8.3-improper-signature-verification-of-oci-webassembly-plugins cve-icon cve-icon
History

Tue, 13 Oct 2026 21:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Tue, 13 Oct 2026 20:30:00 +0000

Type Values Removed Values Added
References

Tue, 13 Oct 2026 08:15:00 +0000

Type Values Removed Values Added
First Time appeared Hyper-mcp-rs
Hyper-mcp-rs hyper-mcp
Vendors & Products Hyper-mcp-rs
Hyper-mcp-rs hyper-mcp

Sun, 11 Oct 2026 13:45:00 +0000

Type Values Removed Values Added
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.
Title hyper-mcp through 0.8.3 Improper Signature Verification of OCI WebAssembly Plugins
Weaknesses CWE-347
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N'}

cvssV4_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'}
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published: 2026-10-11T13:25:59.469Z

Updated: 2026-10-13T19:35:43.889Z

Reserved: 2026-10-10T23:08:36.419Z

Link: CVE-2026-108699

cve-icon Vulnrichment

Updated: 2026-10-13T19:35:36.590Z

cve-icon NVD

Status : Deferred

Published: 2026-10-11T14:17:04.257

Modified: 2026-10-16T19:21:14.417

Link: CVE-2026-108699

cve-icon Redhat

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