CVE-2026-108698CWE-367

CVE-2026-108698

Medium · published October 11, 2026

CVSS v3.1
6.5
EPSS
0%
Percentile
14.6
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N
CVSS v4.0
8.3 · 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
EPSS
0.00243 · 14.6th percentile
Weakness
CWE-367 · Time-of-check Time-of-use (TOCTOU) Race Condition
Published
2026-10-11T18:17Z
References (5)
https://github.com/hyper-mcp-rs/hyper-mcp · [email protected]https://github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/wasm/oci.rs#L193-L224 · [email protected]https://github.com/hyper-mcp-rs/hyper-mcp/blob/v0.8.3/src/wasm/oci.rs#L79-L148 · [email protected]https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/hyper-mcp-oci-signature-manifest-toctou · [email protected]https://www.vulncheck.com/advisories/hyper-mcp-through-0.8.3-oci-plugin-signature-verification-toctou-race-condition · [email protected]
EPSS history
Timeline
  • 13 OCT 03:28Z
    EPSS moved — → 0%
    epss
  • 11 OCT 13:25Z
    hyper-mcp through 0.8.3 OCI Plugin Signature Verification TOCTOU Race Condition
    cvelistv5
  • 11 OCT 13:25Z
    hyper-mcp through 0.8.3 OCI Plugin Signature Verification TOCTOU Race Condition
    cvelistv5