Summary
mpp vulnerable to Gas Draining with low gas limit
Vulnerability
When the server acts as the fee payer, mpp Elixir 0.4.0 (ZenHive/mpp) does not validate whether the gas_limit set by the client is enough before broadcasting. A malicious client can drain the server's gas without paying.
A transferWithMemo call on Tempo Moderato testnet requires ~51,299 gas to complete successfully. By setting gas_limit = 51,298:
- The Tx gets cosigned and broadcast by the server.
- The Tx runs out of gas during EVM execution. All state reverts.
- The server's fee-payer wallet is charged for gas used.
- The client pays nothing and receives no resource.
# Run the PoC
unzip mpp_elixir_low_gas_PoC.zip
cd mpp_elixir_low_gas_PoC
docker build -t mpp-elixir-low-gas .
docker run --rm mpp-elixir-low-gas
Zero-Cost DoS Attack: Unlike gas draining with access list or padding, where the malicious client needs to complete a payment to drain the gas, this vulnerability allows malicious users to continuously drain the server's gas at virtually no financial cost (requiring only computing power). Therefore, an attacker can spawn N malicious clients to completely drain the funds from the server's wallet to perform a Denial of Service (DoS) attack. Once the server's wallet is empty, it has no more funds to pay the gas fees for upcoming requests from legitimate clients.
# Run the DoS PoC
unzip mpp_elixir_low_gas_dos_PoC.zip
cd mpp_elixir_low_gas_dos_PoC
docker build -t mpp-elixir-dos .
docker run --rm mpp-elixir-dos
Vulnerable code path: broadcast_and_verify/7 in mpp/methods/tempo.ex (ZenHive/mpp 0.4.0).
When wait_for_confirmation = true (the default), it calls rpc_broadcast_sync directly without any gas-adequacy check or simulation. The alternative wait_for_confirmation = false path does call simulate_payment_call via eth_call, but that simulation omits the gas parameter and therefore does not catch out-of-gas conditions.
Impact
A malicious client can drain the server's wallet without any financial cost.
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-VJ8P-HP9X-GH47? GHSA-VJ8P-HP9X-GH47 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-VJ8P-HP9X-GH47? mpp (erlang) versions >= 0.2.0, < 0.6.0 is affected.
- Is there a fix for GHSA-VJ8P-HP9X-GH47? Yes. GHSA-VJ8P-HP9X-GH47 is fixed in 0.6.0. Upgrade to this version or later.
- Is GHSA-VJ8P-HP9X-GH47 exploitable, and should I be worried? Whether GHSA-VJ8P-HP9X-GH47 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-VJ8P-HP9X-GH47 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-VJ8P-HP9X-GH47? Upgrade
mppto 0.6.0 or later.