Summary
Weight not properly refunded after EVM execution
Workarounds
None.
References
Are there any links users can visit to find out more?
For more information
If you have any questions or comments about this advisory:
- Open an issue in Frontier repo
- Email Wei
Impact
Previously, the worst case weight was always accounted as the block weight for all cases. In case of large EVM gas refunds, this can lead to block spamming attacks -- the adversary can construct blocks with transactions that have large amount of refunds or unused gases with reverts, and as a result inflate up the chain gas prices. This issue is fixed by properly refund unused weights after each EVM execution.
The impact of this issue is limited in that the spamming attack would still be costly for any adversary, and it has no ability to alter any chain state.
CVE-2022-39242 has a CVSS score of 5.3 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
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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The issue is fixed in https://github.com/paritytech/frontier/pull/851
Frequently Asked Questions
- What is CVE-2022-39242? CVE-2022-39242 is a medium-severity security vulnerability in pallet-ethereum (rust), affecting versions <= 3.0.0. No fixed version is listed yet.
- How severe is CVE-2022-39242? CVE-2022-39242 has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of pallet-ethereum are affected by CVE-2022-39242? pallet-ethereum (rust) versions <= 3.0.0 is affected.
- Is there a fix for CVE-2022-39242? No fixed version is listed for CVE-2022-39242 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2022-39242 exploitable, and should I be worried? Whether CVE-2022-39242 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 CVE-2022-39242 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.