Summary
mpp vulnerable to Gas Draining with no limit
Details
When the server acts as the fee_payer, the mpp Elixir 0.4.0 does not validate gas_limit, max_fee_per_gas and max_priority_fee_per_gas before cosigning the client's fee-payer transaction. A malicious client embeds arbitrarily large max_fee_per_gas and max_priority_fee_per_gas values in the signed envelope. The server cosigns and broadcasts, paying those inflated gas costs from its own wallet based on the effective_gas_price calculated from the high max_fee_per_gas and max_priority_fee_per_gas set by the client.
Vulnerable function: cosign_fee_payer/3 in transaction.ex around lines 229–262.
PoC
The PoC is provided below. It is configured to reproduce the attack on Tempo Moderate testnet within a Docker environment. Download the PoC and run:
unzip mpp_elixir_PoC.zip
cd mpp_elixir
docker build -t mpp-elixir-gasdrain .
docker run --rm mpp-elixir-gasdrain
There are more details in mpp_elixir/README.md
Impact
By draining the server's wallet, an attacker causes direct financial loss to the organization. Furthermore, if the server's funds are drained completely, legitimate clients will have their requests fail, as the server can no longer fund future transactions, effectively creating a Denial of Service (DoS) attack.
The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is GHSA-VV77-66RF-PM86? GHSA-VV77-66RF-PM86 is a high-severity improper input validation vulnerability in mpp (erlang), affecting versions >= 0.2.0, < 0.6.0. It is fixed in 0.6.0. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
- Which versions of mpp are affected by GHSA-VV77-66RF-PM86? mpp (erlang) versions >= 0.2.0, < 0.6.0 is affected.
- Is there a fix for GHSA-VV77-66RF-PM86? Yes. GHSA-VV77-66RF-PM86 is fixed in 0.6.0. Upgrade to this version or later.
- Is GHSA-VV77-66RF-PM86 exploitable, and should I be worried? Whether GHSA-VV77-66RF-PM86 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-VV77-66RF-PM86 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-VV77-66RF-PM86? Upgrade
mppto 0.6.0 or later.