{"id":"CVE-2026-59695","summary":"Unbounded max_fee_per_gas in mpp Tempo fee-payer enables single-request wallet drain","details":"Improper Validation of Specified Quantity in Input in ZenHive mpp allows an unauthenticated remote client to drain the fee-payer wallet in a single request by naming an arbitrarily high gas price.\n\nWhen the mpp Elixir library is configured as fee payer (fee_payer: true), MPP.Tempo.Transaction.cosign_fee_payer/3 re-signs the client-supplied base fields of the 0x76 AASigned envelope verbatim, including max_fee_per_gas and max_priority_fee_per_gas, without validating that they are within reasonable bounds. A malicious client embeds arbitrarily large values for these fields in the signed envelope. The server co-signs and broadcasts the transaction. The effective_gas_price billed against the fee-payer wallet is derived from the attacker-supplied ceilings, so the server pays those inflated per-gas rates out of its own wallet. A single crafted request can drain the wallet entirely, after which the server can no longer sponsor gas for legitimate payment requests.\n\nThis issue affects mpp: from 0.2.0 before 0.6.0.","aliases":["EEF-CVE-2026-59695","GHSA-vv77-66rf-pm86"],"modified":"2026-08-12T03:51:40.105268063Z","published":"2026-07-17T10:11:43.674Z","database_specific":{"cwe_ids":["CWE-1284"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59695.json","unresolved_ranges":[{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"d29d54e507918db00a5b65d90136b73166c017d7"},{"fixed":"5d6338e2334084c5f2a78cfcca474830733ed7e8"}]}],"cna_assigner":"EEF"},"references":[{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-59695.html"},{"type":"WEB","url":"https://github.com"},{"type":"WEB","url":"https://osv.dev/vulnerability/EEF-CVE-2026-59695"},{"type":"WEB","url":"https://repo.hex.pm"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59695.json"},{"type":"ADVISORY","url":"https://github.com/ZenHive/mpp/security/advisories/GHSA-vv77-66rf-pm86"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59695"},{"type":"FIX","url":"https://github.com/ZenHive/mpp/commit/5d6338e2334084c5f2a78cfcca474830733ed7e8"},{"type":"PACKAGE","url":"https://github.com/ZenHive/mpp"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/zenhive/mpp","events":[{"introduced":"7ca7538f05959a98e0e5e63e4bd949b4f362cf8d"},{"fixed":"422bcdd066d1457a93bf5e75fd55e71c5e0be961"},{"fixed":"5d6338e2334084c5f2a78cfcca474830733ed7e8"}],"database_specific":{"extracted_events":[{"introduced":"0.2.0"},{"fixed":"0.6.0"}],"source":["DESCRIPTION","REFERENCES"]}}],"versions":["v0.5.1","v0.4.0","v0.3.0","v0.2.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-59695.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"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"}]}