Summary
Transaction validity oversight in pallet-ethereum
Workarounds
None.
References
Patch PR: https://github.com/paritytech/frontier/pull/465
For more information
If you have any questions or comments about this advisory:
- Open an issue in the Frontier repo
Impact
A bug in pallet-ethereum can cause invalid transactions to be included in the Ethereum block state in pallet-ethereum due to not validating the input data size. Any invalid transactions included this way have no possibility to alter the internal Ethereum or Substrate state. The transaction will appear to have be included, but is of no effect as it is rejected by the EVM engine. The impact is further limited by Substrate extrinsic size constraints.
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.
CVE-2021-39193 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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Patches are applied in PR #465.
Frequently Asked Questions
- What is CVE-2021-39193? CVE-2021-39193 is a medium-severity improper input validation vulnerability in pallet-ethereum (rust), affecting versions <= 3.0.0. No fixed version is listed yet. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
- How severe is CVE-2021-39193? CVE-2021-39193 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-2021-39193? pallet-ethereum (rust) versions <= 3.0.0 is affected.
- Is there a fix for CVE-2021-39193? No fixed version is listed for CVE-2021-39193 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2021-39193 exploitable, and should I be worried? Whether CVE-2021-39193 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-2021-39193 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 CVE-2021-39193? No fixed version is listed yet. In the interim: Validate all external input against an allowlist of expected values, types, and ranges before processing.