{"id":"CVE-2026-73541","aliases":["EEF-CVE-2026-73541","EUVD-2026-62593","GHSA-j4j7-7xpr-c7cr","GHSA-j5gr-9qmc-3234"],"status":"published","title":"Tempo fee sponsorship in mpp bounds each transaction but not aggregate exposure, allowing concurrent sponsor-wallet drain","description":"Allocation of Resources Without Limits or Throttling in ZenHive mpp allows an unauthenticated remote client to drain the fee-payer wallet through concurrent sponsored payments, denying service to legitimate payers once it is empty.\n\nMPP.Methods.Tempo.FeePayerPolicy enforces its ceilings (max_gas, max_fee_per_gas, max_priority_fee_per_gas, the worst-case gas_limit * max_fee_per_gas \u003c= max_total_fee budget cap, and a validity window) against one transaction at a time, and nothing accounts for exposure across concurrent requests. reserve_hash_atomic/2 is keyed on the transaction hash, so it prevents duplicate broadcast of the same signed transaction but not N distinct sponsored transactions carrying distinct expiring nonces. Committed sponsor exposure is therefore N times max_total_fee, bounded by nothing in the library, and the default 900 second validity window lets co-signed transactions stay broadcastable and uncounted for that entire period.\n\nThis issue affects mpp: from 0.2.0 before 0.12.0.","severity":{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00589,"percentile":0.48587,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-770"],"published":"2026-08-19T17:20:00Z","modified":"2026-10-28T02:31:00Z","fixes":[{"ecosystem":"Hex","package":"mpp","fixed_in":["0.12.0"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Hex","package":"mpp","ranges":[{"type":"SEMVER","events":[{"introduced":"0.2.0"},{"fixed":"0.12.0"}]}],"versions":["0.10.0","0.11.0","0.2.0","0.3.0","0.3.1","0.3.2","0.4.0","0.6.0","0.6.1","0.6.2","0.6.3","0.6.4","0.7.0","0.8.0","0.9.0"]}],"products":[{"vendor":"zenhive","product":"machine_payments_protocol"},{"vendor":"zenhive","product":"mpp"}],"references":[{"url":"https://github.com/ZenHive/mpp/security/advisories/GHSA-j4j7-7xpr-c7cr","tags":["vendor-advisory","related","Vendor Advisory","advisory"]},{"url":"https://cna.erlef.org/cves/CVE-2026-73541.html","tags":["related","Third Party Advisory","Mitigation","web"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-73541","tags":["related","Third Party Advisory","Mitigation","web"]},{"url":"https://github.com/ZenHive/mpp/commit/ddc46868fba57ccebb567c04709812b466123076","tags":["patch","Patch","fix"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-73541","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-j5gr-9qmc-3234"},{"url":"https://github.com","tags":["web"]},{"url":"https://repo.hex.pm","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73541.json","tags":["advisory"]},{"url":"https://github.com/ZenHive/mpp","tags":["package"]},{"url":"https://hex.pm/packages/mpp","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-73541","title":"Tempo fee sponsorship in mpp bounds each transaction but not aggregate exposure, allowing concurrent sponsor-wallet drain","description":"Allocation of Resources Without Limits or Throttling in ZenHive mpp allows an unauthenticated remote client to drain the fee-payer wallet through concurrent sponsored payments, denying service to legitimate payers once it is empty.\n\nMPP.Methods.Tempo.FeePayerPolicy enforces its ceilings (max_gas, max_fee_per_gas, max_priority_fee_per_gas, the worst-case gas_limit * max_fee_per_gas \u003c= max_total_fee budget cap, and a validity window) against one transaction at a time, and nothing accounts for exposure across concurrent requests. reserve_hash_atomic/2 is keyed on the transaction hash, so it prevents duplicate broadcast of the same signed transaction but not N distinct sponsored transactions carrying distinct expiring nonces. Committed sponsor exposure is therefore N times max_total_fee, bounded by nothing in the library, and the default 900 second validity window lets co-signed transactions stay broadcastable and uncounted for that entire period.\n\nThis issue affects mpp: from 0.2.0 before 0.12.0.","status":"published","published":"2026-08-19T17:20:00.286Z","modified":"2026-08-19T18:47:04.542Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T13:43:22.599321Z"}],"euvd":[{"id":"EUVD-2026-62593","description":"Allocation of Resources Without Limits or Throttling in ZenHive mpp allows an unauthenticated remote client to drain the fee-payer wallet through concurrent sponsored payments, denying service to legitimate payers once it is empty.\n\nMPP.Methods.Tempo.FeePayerPolicy enforces its ceilings (max_gas, max_fee_per_gas, max_priority_fee_per_gas, the worst-case gas_limit * max_fee_per_gas \u003c= max_total_fee budget cap, and a validity window) against one transaction at a time, and nothing accounts for exposure across concurrent requests. reserve_hash_atomic/2 is keyed on the transaction hash, so it prevents duplicate broadcast of the same signed transaction but not N distinct sponsored transactions carrying distinct expiring nonces. Committed sponsor exposure is therefore N times max_total_fee, bounded by nothing in the library, and the default 900 second validity window lets co-signed transactions stay broadcastable and uncounted for that entire period.\n\nThis issue affects mpp: from 0.2.0 before 0.12.0.","status":"published","published":"2026-08-19T17:20:00Z","modified":"2026-08-19T18:47:04Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-02T18:01:40.9092Z"}],"ghsa":[{"id":"GHSA-j5gr-9qmc-3234","title":"Allocation of Resources Without Limits or Throttling in ZenHive mpp allows an unauthenticated...","description":"Allocation of Resources Without Limits or Throttling in ZenHive mpp allows an unauthenticated remote client to drain the fee-payer wallet through concurrent sponsored payments, denying service to legitimate payers once it is empty.\n\nMPP.Methods.Tempo.FeePayerPolicy enforces its ceilings (max_gas, max_fee_per_gas, max_priority_fee_per_gas, the worst-case gas_limit * max_fee_per_gas \u003c= max_total_fee budget cap, and a validity window) against one transaction at a time, and nothing accounts for exposure across concurrent requests. reserve_hash_atomic/2 is keyed on the transaction hash, so it prevents duplicate broadcast of the same signed transaction but not N distinct sponsored transactions carrying distinct expiring nonces. Committed sponsor exposure is therefore N times max_total_fee, bounded by nothing in the library, and the default 900 second validity window lets co-signed transactions stay broadcastable and uncounted for that entire period.\n\nThis issue affects mpp: from 0.2.0 before 0.12.0.","status":"published","published":"2026-08-19T18:32:54Z","modified":"2026-09-10T18:33:06Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/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"},{"version":"3.1","score":8.2,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H","level":"high"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T15:11:42.667371Z"}],"nvd":[{"id":"CVE-2026-73541","description":"Allocation of Resources Without Limits or Throttling in ZenHive mpp allows an unauthenticated remote client to drain the fee-payer wallet through concurrent sponsored payments, denying service to legitimate payers once it is empty.\n\nMPP.Methods.Tempo.FeePayerPolicy enforces its ceilings (max_gas, max_fee_per_gas, max_priority_fee_per_gas, the worst-case gas_limit * max_fee_per_gas \u003c= max_total_fee budget cap, and a validity window) against one transaction at a time, and nothing accounts for exposure across concurrent requests. reserve_hash_atomic/2 is keyed on the transaction hash, so it prevents duplicate broadcast of the same signed transaction but not N distinct sponsored transactions carrying distinct expiring nonces. Committed sponsor exposure is therefore N times max_total_fee, bounded by nothing in the library, and the default 900 second validity window lets co-signed transactions stay broadcastable and uncounted for that entire period.\n\nThis issue affects mpp: from 0.2.0 before 0.12.0.","status":"published","published":"2026-08-19T18:17:25.627Z","modified":"2026-09-10T18:24:36.653Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/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"},{"version":"3.1","score":8.2,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H","level":"high","assessor":"primary"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T14:12:39.962615Z"}],"osv":[{"id":"CVE-2026-73541","title":"Tempo fee sponsorship in mpp bounds each transaction but not aggregate exposure, allowing concurrent sponsor-wallet drain","description":"Allocation of Resources Without Limits or Throttling in ZenHive mpp allows an unauthenticated remote client to drain the fee-payer wallet through concurrent sponsored payments, denying service to legitimate payers once it is empty.\n\nMPP.Methods.Tempo.FeePayerPolicy enforces its ceilings (max_gas, max_fee_per_gas, max_priority_fee_per_gas, the worst-case gas_limit * max_fee_per_gas \u003c= max_total_fee budget cap, and a validity window) against one transaction at a time, and nothing accounts for exposure across concurrent requests. reserve_hash_atomic/2 is keyed on the transaction hash, so it prevents duplicate broadcast of the same signed transaction but not N distinct sponsored transactions carrying distinct expiring nonces. Committed sponsor exposure is therefore N times max_total_fee, bounded by nothing in the library, and the default 900 second validity window lets co-signed transactions stay broadcastable and uncounted for that entire period.\n\nThis issue affects mpp: from 0.2.0 before 0.12.0.","status":"published","published":"2026-08-19T17:20:00.286Z","modified":"2026-10-28T02:31:00.936751949Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T15:45:16.365946Z"},{"id":"EEF-CVE-2026-73541","title":"Tempo fee sponsorship in mpp bounds each transaction but not aggregate exposure, allowing concurrent sponsor-wallet drain","description":"## Summary\n\nAllocation of Resources Without Limits or Throttling in ZenHive mpp allows an unauthenticated remote client to drain the fee-payer wallet through concurrent sponsored payments, denying service to legitimate payers once it is empty.\n\n`MPP.Methods.Tempo.FeePayerPolicy` enforces its ceilings (`max_gas`, `max_fee_per_gas`, `max_priority_fee_per_gas`, the worst-case `gas_limit * max_fee_per_gas \u003c= max_total_fee` budget cap, and a validity window) against one transaction at a time, and nothing accounts for exposure across concurrent requests. `reserve_hash_atomic/2` is keyed on the transaction hash, so it prevents duplicate broadcast of the same signed transaction but not N distinct sponsored transactions carrying distinct expiring nonces. Committed sponsor exposure is therefore N times `max_total_fee`, bounded by nothing in the library, and the default 900 second validity window lets co-signed transactions stay broadcastable and uncounted for that entire period.\n\nThis issue affects mpp: from 0.2.0 before 0.12.0.\n\n## Workarounds\n\nDisable Tempo fee sponsorship by setting `\"fee_payer\" =\u003e false` (the default), so the client pays its own gas and the sponsor wallet is never committed. Where sponsorship must stay enabled, lowering `max_total_fee` and `max_validity_window_seconds` reduces the exposure each concurrent request can commit and how long it stays outstanding, without bounding the aggregate.\n\n## Configurations\n\nOnly deployments that enable Tempo server-side fee sponsorship are affected, through `\"fee_payer\" =\u003e true` in `method_config` with either local co-signing (`fee_payer_private_key`) or hosted sponsorship (`fee_payer_url`). Sponsorship is disabled by default.","status":"published","published":"2026-08-19T17:20:00.286Z","modified":"2026-09-08T05:45:02.681764011Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T15:46:33.520522Z"}]}}