CVE-2026-108698
hyper-mcp through 0.8.3 OCI Plugin Signature Verification TOCTOU Race Condition
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-367 |
| Vendor | hyper-mcp-rs |
| Product | hyper-mcp |
| Published | Oct 11, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
High
Availability
None
Affected Versions
hyper-mcp-rs / hyper-mcp
0 ≤ 0.8.3
References
hackmd.io: https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/hyper-mcp-oci-signature-manifest-toctou github.com: https://github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/wasm/oci.rs#L79-L148 github.com: https://github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/wasm/oci.rs#L193-L224 github.com: https://github.com/hyper-mcp-rs/hyper-mcp vulncheck.com: https://www.vulncheck.com/advisories/hyper-mcp-through-0.8.3-oci-plugin-signature-verification-toctou-race-condition
Credits
hieuPenguinnn