---
id: CVE-2026-108699
title: >-
  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
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 …
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N'
cwe:
  - CWE-347
published: '2026-10-11'
updated: '2026-10-11'
sourceUpdated: '2026-10-11T14:17:04.257'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-108699'
references:
  - url: 'https://github.com/hyper-mcp-rs/hyper-mcp'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/config.rs#L138-L170
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/wasm/oci.rs#L157-L190
    label: disclosure@vulncheck.com
  - url: >-
      https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/hyper-mcp-oci-signature-manifest-toctou
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/hyper-mcp-through-0.8.3-improper-signature-verification-of-oci-webassembly-plugins
    label: disclosure@vulncheck.com
tags:
  - nvd
ingestedAt: '2026-10-12T14:50:34.050Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.