{"id":"CVE-2026-73541","state":"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 <= 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.","publishedAt":"2026-08-19T17:20:00.286Z","updatedAt":"2026-08-19T18:47:04.542Z","severity":{"score":8.3,"label":"High","version":"4.0","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","source":"EEF"},"assigner":"EEF","products":["ZenHive mpp"],"affected":[{"vendor":"ZenHive","product":"mpp","packageName":"mpp","packageURL":"pkg:hex/mpp","defaultStatus":"unaffected","versions":[{"version":"0.2.0","status":"affected","lessThan":"0.12.0","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:ZenHive:mpp:*:*:*:*:*:*:*:*"],"modules":["'Elixir.MPP.Methods.Tempo.FeePayerPolicy'","'Elixir.MPP.Methods.Tempo'"],"programFiles":["lib/mpp/methods/tempo/fee_payer_policy.ex","lib/mpp/methods/tempo.ex"],"programRoutines":[{"name":"'Elixir.MPP.Methods.Tempo.FeePayerPolicy':validate/3"},{"name":"'Elixir.MPP.Methods.Tempo':verify/2"}],"repo":"https://github.com/ZenHive/mpp"},{"vendor":"ZenHive","product":"mpp","packageName":"zenhive/mpp","packageURL":"pkg:github/zenhive/mpp","defaultStatus":"unaffected","versions":[{"version":"d29d54e507918db00a5b65d90136b73166c017d7","status":"affected","lessThan":"ddc46868fba57ccebb567c04709812b466123076","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:ZenHive:mpp:*:*:*:*:*:*:*:*"],"modules":["'Elixir.MPP.Methods.Tempo.FeePayerPolicy'","'Elixir.MPP.Methods.Tempo'"],"programFiles":["lib/mpp/methods/tempo/fee_payer_policy.ex","lib/mpp/methods/tempo.ex"],"programRoutines":[{"name":"'Elixir.MPP.Methods.Tempo.FeePayerPolicy':validate/3"},{"name":"'Elixir.MPP.Methods.Tempo':verify/2"}],"repo":"https://github.com/ZenHive/mpp"}],"references":["https://github.com/ZenHive/mpp/security/advisories/GHSA-j4j7-7xpr-c7cr","https://cna.erlef.org/cves/CVE-2026-73541.html","https://osv.dev/vulnerability/EEF-CVE-2026-73541","https://github.com/ZenHive/mpp/commit/ddc46868fba57ccebb567c04709812b466123076"],"weaknesses":["CWE-770"],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/73xxx/CVE-2026-73541.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-73541","state":"PUBLISHED","datePublished":"2026-08-19T17:20:00.286Z","dateUpdated":"2026-08-19T18:47:04.542Z","assignerShortName":"EEF","assignerOrgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateReserved":"2026-08-18T10:00:02.140Z"},"containers":{"cna":{"title":"Tempo fee sponsorship in mpp bounds each transaction but not aggregate exposure, allowing concurrent sponsor-wallet drain","descriptions":[{"lang":"en","value":"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 <= 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."}],"affected":[{"vendor":"ZenHive","product":"mpp","packageName":"mpp","packageURL":"pkg:hex/mpp","defaultStatus":"unaffected","versions":[{"version":"0.2.0","status":"affected","lessThan":"0.12.0","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:ZenHive:mpp:*:*:*:*:*:*:*:*"],"modules":["'Elixir.MPP.Methods.Tempo.FeePayerPolicy'","'Elixir.MPP.Methods.Tempo'"],"programFiles":["lib/mpp/methods/tempo/fee_payer_policy.ex","lib/mpp/methods/tempo.ex"],"programRoutines":[{"name":"'Elixir.MPP.Methods.Tempo.FeePayerPolicy':validate/3"},{"name":"'Elixir.MPP.Methods.Tempo':verify/2"}],"repo":"https://github.com/ZenHive/mpp"},{"vendor":"ZenHive","product":"mpp","packageName":"zenhive/mpp","packageURL":"pkg:github/zenhive/mpp","defaultStatus":"unaffected","versions":[{"version":"d29d54e507918db00a5b65d90136b73166c017d7","status":"affected","lessThan":"ddc46868fba57ccebb567c04709812b466123076","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:ZenHive:mpp:*:*:*:*:*:*:*:*"],"modules":["'Elixir.MPP.Methods.Tempo.FeePayerPolicy'","'Elixir.MPP.Methods.Tempo'"],"programFiles":["lib/mpp/methods/tempo/fee_payer_policy.ex","lib/mpp/methods/tempo.ex"],"programRoutines":[{"name":"'Elixir.MPP.Methods.Tempo.FeePayerPolicy':validate/3"},{"name":"'Elixir.MPP.Methods.Tempo':verify/2"}],"repo":"https://github.com/ZenHive/mpp"}],"references":[{"url":"https://github.com/ZenHive/mpp/security/advisories/GHSA-j4j7-7xpr-c7cr","tags":["vendor-advisory","related"]},{"url":"https://cna.erlef.org/cves/CVE-2026-73541.html","tags":["related"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-73541","tags":["related"]},{"url":"https://github.com/ZenHive/mpp/commit/ddc46868fba57ccebb567c04709812b466123076","tags":["patch"]}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":8.3,"baseSeverity":"HIGH","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"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","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-770","description":"CWE-770 Allocation of Resources Without Limits or Throttling","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"EEF","orgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateUpdated":"2026-08-19T17:20:00.286Z"},"configurations":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"<p>Only deployments that enable Tempo server-side fee sponsorship are affected, through <code>\"fee_payer\" =&gt; true</code> in <code>method_config</code> with either local co-signing (<code>fee_payer_private_key</code>) or hosted sponsorship (<code>fee_payer_url</code>). Sponsorship is disabled by default.</p>"},{"base64":false,"type":"text/markdown","value":"Only deployments that enable Tempo server-side fee sponsorship are affected, through `\"fee_payer\" => true` in `method_config` with either local co-signing (`fee_payer_private_key`) or hosted sponsorship (`fee_payer_url`). Sponsorship is disabled by default."}],"value":"Only deployments that enable Tempo server-side fee sponsorship are affected, through \"fee_payer\" => true in method_config with either local co-signing (fee_payer_private_key) or hosted sponsorship (fee_payer_url). Sponsorship is disabled by default."}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:a:ZenHive:mpp:*:*:*:*:*:*:*:*","versionEndExcluding":"0.12.0","versionStartIncluding":"0.2.0","vulnerable":true}],"negate":false,"operator":"OR"}],"operator":"AND"}],"credits":[{"lang":"en","type":"finder","value":"E.FU"},{"lang":"en","type":"remediation developer","value":"E.FU"},{"lang":"en","type":"analyst","value":"Jonatan Männchen / EEF"}],"datePublic":"2026-08-02T00:00:00.000Z","impacts":[{"capecId":"CAPEC-130","descriptions":[{"lang":"en","value":"CAPEC-130 Excessive Allocation"}]}],"source":{"discovery":"EXTERNAL"},"workarounds":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"<p>Disable Tempo fee sponsorship by setting <code>\"fee_payer\" =&gt; false</code> (the default), so the client pays its own gas and the sponsor wallet is never committed. Where sponsorship must stay enabled, lowering <code>max_total_fee</code> and <code>max_validity_window_seconds</code> reduces the exposure each concurrent request can commit and how long it stays outstanding, without bounding the aggregate.</p>"},{"base64":false,"type":"text/markdown","value":"Disable Tempo fee sponsorship by setting `\"fee_payer\" => 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."}],"value":"Disable Tempo fee sponsorship by setting \"fee_payer\" => 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."}]},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-19T18:45:45.477502Z","id":"CVE-2026-73541","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-19T18:47:04.542Z"}}]}}}