{"id":"CVE-2026-87119","aliases":["EEF-CVE-2026-87119","EUVD-2026-84361","GHSA-h97r-55w6-6rfg","GHSA-p9fv-9w58-95x2"],"status":"published","title":"mpp Tempo subscription key authorization is not bound to the issuing challenge, allowing a captured activation credential to be replayed","description":"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.","severity":{"version":"4.0","score":8.2,"vector":"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","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00574,"percentile":0.47864,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-294"],"published":"2026-09-22T11:16:56Z","modified":"2026-10-28T02:31:05Z","fixes":[{"ecosystem":"Hex","package":"mpp","fixed_in":["0.16.2"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Hex","package":"mpp","ranges":[{"type":"SEMVER","events":[{"introduced":"0.14.0"},{"fixed":"0.16.2"}]}],"versions":["0.14.0","0.15.0","0.16.0","0.16.1"]}],"products":[{"vendor":"zenhive","product":"mpp"}],"references":[{"url":"https://github.com/ZenHive/mpp/security/advisories/GHSA-p9fv-9w58-95x2","tags":["related","vendor-advisory","advisory"]},{"url":"https://cna.erlef.org/cves/CVE-2026-87119.html","tags":["related","web"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-87119","tags":["related","web"]},{"url":"https://github.com/ZenHive/mpp/commit/db464dfa9a86ccda58f0827101f6da6bd8aafa78","tags":["related","fix","web"]},{"url":"https://github.com/ZenHive/mpp/commit/4b6eaec02af0e8485cfb4ff68f467d075ed5dd6f","tags":["patch","fix"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-87119","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-h97r-55w6-6rfg"},{"url":"https://github.com","tags":["web"]},{"url":"https://repo.hex.pm","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/87xxx/CVE-2026-87119.json","tags":["advisory"]},{"url":"https://github.com/ZenHive/mpp","tags":["package"]},{"url":"https://hex.pm/packages/mpp","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-87119","title":"mpp Tempo subscription key authorization is not bound to the issuing challenge, allowing a captured activation credential to be replayed","description":"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.","status":"published","published":"2026-09-22T11:16:56.232Z","modified":"2026-09-22T12:02:31.484Z","cvss":[{"version":"4.0","score":8.2,"vector":"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","level":"high","assessor":"cna"}],"cwes":["CWE-294"],"updated_at":"2026-11-02T13:37:47.463822Z"}],"euvd":[{"id":"EUVD-2026-84361","description":"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.","status":"published","published":"2026-09-22T11:16:56Z","modified":"2026-09-22T12:02:31Z","cvss":[{"version":"4.0","score":8.2,"vector":"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","level":"high"}],"updated_at":"2026-11-02T17:28:03.363938Z"}],"ghsa":[{"id":"GHSA-h97r-55w6-6rfg","title":"Authentication Bypass by Capture-replay in ZenHive mpp allows an attacker holding a captured...","description":"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.","status":"published","published":"2026-09-22T12:30:26Z","modified":"2026-09-22T12:30:32Z","cvss":[{"version":"4.0","score":8.2,"vector":"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","level":"high"}],"cwes":["CWE-294"],"updated_at":"2026-11-02T15:12:17.163357Z"}],"nvd":[{"id":"CVE-2026-87119","description":"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.","status":"published","published":"2026-09-22T12:17:14.15Z","modified":"2026-09-22T19:09:32.273Z","cvss":[{"version":"4.0","score":8.2,"vector":"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","level":"high","assessor":"secondary"}],"cwes":["CWE-294"],"updated_at":"2026-11-02T14:12:50.368368Z"}],"osv":[{"id":"CVE-2026-87119","title":"mpp Tempo subscription key authorization is not bound to the issuing challenge, allowing a captured activation credential to be replayed","description":"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.","status":"published","published":"2026-09-22T11:16:56.232Z","modified":"2026-10-28T02:31:05.734940053Z","cvss":[{"version":"4.0","score":8.2,"vector":"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","level":"high"}],"cwes":["CWE-294"],"updated_at":"2026-11-02T15:45:19.210277Z"},{"id":"EEF-CVE-2026-87119","title":"mpp Tempo subscription key authorization is not bound to the issuing challenge, allowing a captured activation credential to be replayed","description":"## Summary\n\nAuthentication 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.\n\n## Impact\n\nAn attacker who obtains a payer's subscription activation credential (from a non-TLS hop, a log, a compromised intermediary, or the client's own retry buffer) can present it under fresh challenges to settle repeated first-period charges against that payer's wallet and re-authorize the server's access key. The payer bears the on-chain cost, limited only by the per-period subscription limit and the subscription expiry.\n\n## Configurations\n\nOnly deployments offering Tempo subscriptions are affected, which requires `subscription_access_key_private_key` in the Tempo `method_config`. Exploitation further requires the attacker to have obtained a payer's signed activation credential, in transit over a hop that is not TLS-protected or at rest in a log, an intermediary, or a client retry buffer.","status":"published","published":"2026-09-22T11:16:56.232Z","modified":"2026-09-22T11:40:55.168831655Z","cvss":[{"version":"4.0","score":8.2,"vector":"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","level":"high"}],"cwes":["CWE-294"],"updated_at":"2026-11-02T15:46:33.520522Z"}]}}