EUVD-2026-84361
GHSA-h97r-55w6-6rfg
Severity by source
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Network-reachable and needs no server account (PR:N), but requires a captured credential and replay timing (AC:H); impact is unauthorized financial settlements to the payer (I:H) with no confidentiality or availability loss.
Primary rating from Vendor (EEF).
CVSS VectorVendor: EEF
Lifecycle Timeline
3DescriptionCVE.org
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.
AnalysisAI
Replay of a captured Tempo subscription credential in ZenHive mpp 0.14.0 through 0.16.1 lets an attacker who already holds a validly signed Tempo KeyAuthorization repeatedly charge the same payer's wallet. The signed authorization is bound only to chain id, key type, key id, expiry, limits, and scopes - never to the challenge that prompted it - so it verifies against every challenge the server issues for the same subscription terms, and because Subscription.activate/4 deduplicates activations solely by challenge id, a fresh challenge yields a new dedup key and the settlement transaction is rebuilt and broadcast again. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the attacker to already possess a captured, validly-signed Tempo KeyAuthorization credential for an existing subscription (AT:P) - the credential is signed only over chain id, key type, key id, expiry, limits, and scopes, with no binding to the challenge nonce, and verify/3 pins it against a static per-endpoint server key. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | This is a genuine, high-value integrity flaw rather than an inflated high-CVSS number. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Upgrade the mpp dependency to 0.16.2, the first release outside the vulnerable "from 0.14.0 before 0.16.2" range; the vendor advisory GHSA-p9fv-9w58-95x2 and the linked commits db464dfa9a86ccda58f0827101f6da6bd8aafa78 and 4b6eaec02af0e8485cfb4ff68f467d075ed5dd6f carry the fixes, which add subscription-intent validation and a dedicated MPP.Subscription.ETSStore alongside the session store, extend validate_kind/3 to check the intent as well as the method, and add challenge-expiry validation on the client/provider path. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, create a complete inventory of ZenHive mpp deployments and confirm which run versions 0.14.0 through 0.16.1, contact the vendor to obtain the fixed release and confirm the exact patched version number, and temporarily restrict network access to the Tempo subscription and settlement endpoints to trusted sources only. …
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Same weakness CWE-294 – Authentication Bypass by Capture-replay
View allSame technique Authentication Bypass
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External POC / Exploit Code
Leaving vuln.today