hyper-mcp up to 0.8.3 Signature Verification src/wasm/oci.rs load_wasm toctou

CVSS Meta Temp Score
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CTI Interest Score
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6.9$0-$5k2.47-

Summaryinfo

A vulnerability identified as critical has been detected in hyper-mcp up to 0.8.3. This affects the function load_wasm of the file src/wasm/oci.rs of the component Signature Verification. This manipulation causes toctou. This vulnerability is tracked as CVE-2026-108698. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability has been found in hyper-mcp up to 0.8.3 and classified as critical. Affected by this vulnerability is the function load_wasm of the file src/wasm/oci.rs of the component Signature Verification. The manipulation with an unknown input leads to a toctou vulnerability. The CWE definition for the vulnerability is CWE-367. The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. This can cause the product to perform invalid actions when the resource is in an unexpected state. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE 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 advisory is shared at hackmd.io. This vulnerability is known as CVE-2026-108698 since 10/11/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Type

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 6.9
VulDB Meta Temp Score: 6.9

VulDB Base Score: 7.3
VulDB Temp Score: 7.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 6.5
CNA Vector (VulnCheck): 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Toctou
CWE: CWE-367 / CWE-362
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

10/11/2026 Advisory disclosed
10/11/2026 +0 days CVE reserved
10/11/2026 +0 days VulDB entry created
10/11/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: hackmd.io
Status: Not defined

CVE: CVE-2026-108698 (🔒)
GCVE (CVE): GCVE-0-2026-108698
GCVE (VulDB): GCVE-100-416677

Entryinfo

Created: 10/11/2026 15:55
Changes: 10/11/2026 15:55 (75)
Complete: 🔍
Cache ID: 216::103

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