hyper-mcp through 0.8.3 contains a signature verification bypass vulnerability in load_wasm in src/wasm/oci.rs that verifies the Cosign signature of a separately resolved tag rather than the loaded manifest. Attackers controlling registry responses for the tag can serve an unsigned malicious manifest to the loader and a signed one to Cosign, executing unsigned WebAssembly plugins with configured host capabilities.

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.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
hyper-mcp-rs hyper-mcp unaffected
Version Status Constraints
0 affected ≤ 0.8.3

No data.

No data.

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Project Subscriptions

No data.

Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

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/wasm/oci.rs#L193-L224 cve-icon cve-icon
https://github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/wasm/oci.rs#L79-L148 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-oci-plugin-signature-verification-toctou-race-condition cve-icon cve-icon
History

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

Type Values Removed Values Added
Description hyper-mcp through 0.8.3 contains a signature verification bypass vulnerability in load_wasm in src/wasm/oci.rs that verifies the Cosign signature of a separately resolved tag rather than the loaded manifest. Attackers controlling registry responses for the tag can serve an unsigned malicious manifest to the loader and a signed one to Cosign, executing unsigned WebAssembly plugins with configured host capabilities.
Title hyper-mcp through 0.8.3 OCI Plugin Signature Verification TOCTOU Race Condition
Weaknesses CWE-367
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'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-11T13:25:58.805Z

Reserved: 2026-10-10T23:08:36.107Z

Link: CVE-2026-108698

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-11T14:17:04.113

Modified: 2026-10-11T14:17:04.113

Link: CVE-2026-108698

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses