CVE-2026-59695
Unbounded max_fee_per_gas in mpp Tempo fee-payer enables single-request wallet drain
Description
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. When 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. This issue affects mpp: from 0.2.0 before 0.6.0.
INFO
Published Date :
July 17, 2026, 11:17 a.m.
Last Modified :
July 17, 2026, 11:17 a.m.
Remotely Exploit :
Yes !
Source :
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Affected Products
The following products are affected by CVE-2026-59695
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | HIGH | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | ||||
| CVSS 4.0 | HIGH | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db |
Solution
- Update mpp to version 0.6.0 or later.
- Validate gas prices in transaction requests.
- Configure mpp with fee_payer: false.
- Monitor fee-payer wallet usage.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-59695.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-59695 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-59695
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-59695 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-59695 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Jul. 17, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:2.3:a:ZenHive:mpp:*:*:*:*:*:*:*:*'], 'repo': 'https://github.com/ZenHive/mpp', 'vendor': 'ZenHive', 'modules': ["'Elixir.MPP.Tempo.Transaction'"], 'product': 'mpp', 'versions': [{'status': 'affected', 'version': '0.2.0', 'lessThan': '0.6.0', 'versionType': 'semver'}], 'packageURL': 'pkg:hex/mpp', 'packageName': 'mpp', 'programFiles': ['lib/mpp/tempo/transaction.ex'], 'collectionURL': 'https://repo.hex.pm', 'defaultStatus': 'unaffected', 'programRoutines': [{'name': "'Elixir.MPP.Tempo.Transaction':cosign_fee_payer/3"}]}, {'cpes': ['cpe:2.3:a:ZenHive:mpp:*:*:*:*:*:*:*:*'], 'repo': 'https://github.com/ZenHive/mpp', 'vendor': 'ZenHive', 'modules': ["'Elixir.MPP.Tempo.Transaction'"], 'product': 'mpp', 'versions': [{'status': 'affected', 'version': 'd29d54e507918db00a5b65d90136b73166c017d7', 'lessThan': '5d6338e2334084c5f2a78cfcca474830733ed7e8', 'versionType': 'git'}], 'packageURL': 'pkg:github/ZenHive/mpp', 'packageName': 'ZenHive/mpp', 'programFiles': ['lib/mpp/tempo/transaction.ex'], 'collectionURL': 'https://github.com', 'defaultStatus': 'unaffected', 'programRoutines': [{'name': "'Elixir.MPP.Tempo.Transaction':cosign_fee_payer/3"}]}] Added Description 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. When 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. This issue affects mpp: from 0.2.0 before 0.6.0. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-1284 Added Reference https://cna.erlef.org/cves/CVE-2026-59695.html Added Reference https://github.com/ZenHive/mpp/commit/5d6338e2334084c5f2a78cfcca474830733ed7e8 Added Reference https://github.com/ZenHive/mpp/security/advisories/GHSA-vv77-66rf-pm86 Added Reference https://osv.dev/vulnerability/EEF-CVE-2026-59695