{"id":"CVE-2026-87119","summary":"mpp Tempo subscription key authorization is not bound to the issuing challenge, allowing a captured activation credential to be replayed","details":"Authentication Bypass by Capture-replay in ZenHive mpp allows an attacker holding a captured subscription activation credential to charge the payer repeatedly.\n\nThe 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.\n\nThis issue affects mpp: from 0.14.0 before 0.16.2.","aliases":["EEF-CVE-2026-87119","GHSA-p9fv-9w58-95x2"],"modified":"2026-09-24T03:47:10.084237266Z","published":"2026-09-22T11:16:56.232Z","database_specific":{"unresolved_ranges":[{"extracted_events":[{"introduced":"db464dfa9a86ccda58f0827101f6da6bd8aafa78"},{"fixed":"4b6eaec02af0e8485cfb4ff68f467d075ed5dd6f"}],"source":"AFFECTED_FIELD"}],"cna_assigner":"EEF","cwe_ids":["CWE-294"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/87xxx/CVE-2026-87119.json"},"references":[{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-87119.html"},{"type":"WEB","url":"https://github.com"},{"type":"WEB","url":"https://osv.dev/vulnerability/EEF-CVE-2026-87119"},{"type":"WEB","url":"https://repo.hex.pm"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/87xxx/CVE-2026-87119.json"},{"type":"ADVISORY","url":"https://github.com/ZenHive/mpp/security/advisories/GHSA-p9fv-9w58-95x2"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-87119"},{"type":"FIX","url":"https://github.com/ZenHive/mpp/commit/4b6eaec02af0e8485cfb4ff68f467d075ed5dd6f"},{"type":"FIX","url":"https://github.com/ZenHive/mpp/commit/db464dfa9a86ccda58f0827101f6da6bd8aafa78"},{"type":"PACKAGE","url":"https://github.com/ZenHive/mpp"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/zenhive/mpp","events":[{"introduced":"ad394b7df40e014eefb9f2f5ca2127326a005c3f"},{"fixed":"3b7e43abf60fa30c40985e4043965ec67791b4dc"},{"fixed":"4b6eaec02af0e8485cfb4ff68f467d075ed5dd6f"},{"fixed":"db464dfa9a86ccda58f0827101f6da6bd8aafa78"}],"database_specific":{"extracted_events":[{"introduced":"0.14.0"},{"fixed":"0.16.2"}],"source":["DESCRIPTION","REFERENCES"]}}],"versions":["v0.16.1","v0.16.0","v0.15.0","v0.14.0"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-87119.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"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"}]}