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.
Project Subscriptions
No advisories yet.
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
Tue, 22 Sep 2026 12:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Zenhive
Zenhive mpp |
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| Vendors & Products |
Zenhive
Zenhive mpp |
Tue, 22 Sep 2026 12:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Tue, 22 Sep 2026 11:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | mpp Tempo subscription key authorization is not bound to the issuing challenge, allowing a captured activation credential to be replayed | |
| First Time appeared |
Zenhive
Zenhive mpp |
|
| Weaknesses | CWE-294 | |
| CPEs | cpe:2.3:a:ZenHive:mpp:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Zenhive
Zenhive mpp |
|
| References |
|
|
| Metrics |
cvssV4_0
|
Projects
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Status: PUBLISHED
Assigner: EEF
Published:
Updated: 2026-09-22T12:02:31.484Z
Reserved: 2026-09-11T18:00:02.032Z
Link: CVE-2026-87119
Updated: 2026-09-22T12:02:21.205Z
Status : Received
Published: 2026-09-22T12:17:14.150
Modified: 2026-09-22T12:17:14.150
Link: CVE-2026-87119
No data.
OpenCVE Enrichment
Updated: 2026-09-22T12:30:07Z