# CVE-2026-59252: Missing gas_limit validation in mpp Tempo fee-payer enables wallet drain

> Attackers can drain the fee-payer wallet by submitting transactions with insufficient gas limits, causing denial of service for legitimate users.

- **Severity:** High 8.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Jul 2026
- **Updated:** 18 Jul 2026
- **Also known as:** EEF-CVE-2026-59252, GHSA-vj8p-hp9x-gh47, GHSA-vp7w-82cm-hj3h

## What is CVE-2026-59252?

CVE-2026-59252 is a high-severity vulnerability in ZenHive mpp, published on 17 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Improper Validation of Specified Quantity in Input in ZenHive mpp allows an unauthenticated remote client to drain the fee-payer wallet, resulting in denial of service for legitimate clients.

When the mpp Elixir library is configured as fee payer (fee_payer: true), the MPP.Methods.Tempo payment method co-signs and broadcasts a client-supplied EVM transaction without first validating that the client-supplied gas_limit is sufficient to complete the intended call. A malicious client can submit a signed transferWithMemo transaction with gas_limit deliberately set just below the amount required for successful execution. The server co-signs the transaction and broadcasts it via rpc_broadcast_sync. The transaction runs out of gas during EVM execution and reverts, but the fee-payer wallet is still charged for the burned gas while the client pays nothing and receives no resource. Repeated requests from one or more malicious clients drain the fee-payer wallet at near-zero cost to the attacker, ultimately preventing the server from sponsoring gas for legitimate payment requests.

The wait_for_confirmation = false (optimistic) path is also affected: it invokes simulate_payment_call via eth_call, but that simulation omits the gas parameter and therefore does not catch out-of-gas conditions.

This issue affects mpp: from 0.2.0 before 0.6.0.

Weakness: CWE-1284 (Improper Validation of Specified Quantity in Input)

## Which versions are affected by CVE-2026-59252?

3 open source packages ship an affected version, including mpp.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mpp` | Hex | From 0.2.0 | 0.6.0 |
| `mpp` | Hex | From 0.2.0 | 0.6.0 |
| `mpp` | Hex | From 0.2.0 | 0.6.0 |

## How do I fix CVE-2026-59252?

Upgrade mpp to 0.6.0 or later.

## Is CVE-2026-59252 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-59252 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-59252 and fix it if it is affected.

What it is: CVE-2026-59252 is a high-severity vulnerability in ZenHive mpp, published on 17 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-59252 exists.

Affected packages and fixed versions:
- mpp (Hex): affected from 0.2.0; fixed in 0.6.0
- mpp (Hex): affected from 0.2.0; fixed in 0.6.0
- mpp (Hex): affected from 0.2.0; fixed in 0.6.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-59252/ (Markdown: https://insights.sbomify.com/CVE-2026-59252/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-59252
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-59252
- OSV: https://osv.dev/vulnerability/CVE-2026-59252

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-59252/
Summaries are generated and may contain mistakes; the official description above is the record.