CVE-2026-73541 Denial of service in mpp
An unauthenticated attacker can drain a sponsor wallet via concurrent transactions, causing denial of service for legitimate users.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-73541?
CVE-2026-73541 is a high-severity denial of service vulnerability in ZenHive mpp, published on 19 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-770
Which versions are affected by CVE-2026-73541?
1 open source package ship an affected version, including mpp. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
mpp Hex | From 0.2.0 | 0.12.0 |
Products include Zenhive Machine Payments Protocol.
How do I fix CVE-2026-73541?
Upgrade mpp to 0.12.0 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-73541 being exploited?
There is no known exploitation of CVE-2026-73541 in the wild and no public exploit code.
Other vulnerabilities in ZenHive mpp
- CVE-2026-67581 On-chain transfer proof is not single-use in mpp EVM payment method, enabling cross-challenge replay
- CVE-2026-73136 Static memo configuration in mpp Tempo disables per-challenge attribution binding, enabling third-party replay
- CVE-2026-73829 Non-atomic hash-credential dedup in mpp Tempo allows replay of a confirmed payment under a concurrent race
Sources
Also known as EEF-CVE-2026-73541, GHSA-j4j7-7xpr-c7cr, GHSA-j5gr-9qmc-3234.