ZenHive mpp up to 0.16.1 Tempo key_authorization.ex MPP.Methods.Tempo.KeyAuthorization.verify authentication replay

Summaryinfo

A vulnerability marked as critical has been reported in ZenHive mpp up to 0.16.1. This affects the function MPP.Methods.Tempo.KeyAuthorization.verify of the file lib/mpp/methods/tempo/key_authorization.ex of the component Tempo. Performing a manipulation results in authentication replay. This vulnerability is known as CVE-2026-87119. Remote exploitation of the attack is possible. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in ZenHive mpp up to 0.16.1. This affects the function MPP.Methods.Tempo.KeyAuthorization.verify of the file lib/mpp/methods/tempo/key_authorization.ex of the component Tempo. The manipulation with an unknown input leads to a authentication replay vulnerability. CWE is classifying the issue as CWE-294. A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes). This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Authentication Bypass by Capture-replay in ZenHive mpp allows an attacker holding a captured subscription activation credential to charge the payer repeatedly. The payer signs a Tempo KeyAuthorization over the chain id, key type, key id, expiry, limits and scopes only, with nothing tying it to the challenge that prompted it. MPP.Methods.Tempo.KeyAuthorization.verify/3 in lib/mpp/methods/tempo/key_authorization.ex pins each of those signed fields against the subscription request, and the access key it pins is a static per-endpoint server key, so one signed authorization verifies against every challenge the server issues for the same subscription terms. MPP.Methods.Tempo.Subscription.activate/4 deduplicates activations by challenge id, so presenting the captured credential under a fresh challenge produces a different dedup key, claim_activation succeeds, and the subscription transaction is built and broadcast again. Each replay charges the payer's wallet a new first-period settlement and re-authorizes the server key, bounded only by the subscription expiry and the chain's own semantics for re-installing an existing key. This issue affects mpp: from 0.14.0 before 0.16.2.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-87119 since 09/11/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1040 for this issue.

Upgrading to version 0.16.2 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-84361). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Vendor

• ZenHive

Name

• mpp

Version

• 0.16.0
• 0.16.1

Website

• Product: https://github.com/ZenHive/mpp/

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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