CVE-2026-108699 Details
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.
A vulnerability exists in hyper-mcp versions through 0.8.3, allowing for improper verification of signatures on WebAssembly plugins loaded from OCI registries. This flaw enables attackers to introduce malicious plugins because the signature verification process, handled by Cosign, defaults to accepting any signer identity and OIDC issuer. As a result, an attacker could exploit a plugin image reference by signing it with a free Sigstore keyless certificate, bypassing verification and executing the plugin with the assigned host, filesystem, and environment capabilities.
Update to hyper-mcp version 0.8.4 or later, where this vulnerability has been addressed.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Oct 11, 2026CISA-ADP
Assessed Oct 13, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-347 | Improper Verification of Cryptographic Signature | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| hyper-mcp | <= 0.8.3 (semver) |
CPE
Remediation
| |
Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Oct 13, 2026 | CVE Modified | CISA-ADP |
| Oct 11, 2026 | New CVE Received | [email protected] |