CVE-2026-73541

Tempo fee sponsorship in mpp bounds each transaction but not aggregate exposure, allowing concurrent sponsor-wallet drain

HIGH
8.2
CVSS Score
Published: August 19, 2026 at 05:20 PM UTC
Updated: September 10, 2026 at 06:38 PM UTC
1 product affected across 1 vendorMachine Payments Protocol

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Severity
HIGH8.2
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

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. 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 <= 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. This issue affects mpp: from 0.2.0 before 0.12.0.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0.2.0 ≤ v < 0.12.00.2.0d29d54e507918db00a5b65d90136b73166c017d7
Vendor states this is fixed in ddc46868fba57ccebb567c04709812b466123076 (fixed)
Affected range stops below 0.12.0, so it looks safe — our inference, not a vendor statement

References (4)

RelatedThird Party AdvisoryMitigation
Source: cverecord
https://cna.erlef.org/cves/CVE-2026-73541.html
RelatedThird Party AdvisoryMitigation
Source: cverecord
https://osv.dev/vulnerability/EEF-CVE-2026-73541

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-770

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