CVE-2021-41138

Validity check for signed Frontier-specific extrinsic not called in block execution

Description

Frontier is Substrate's Ethereum compatibility layer. In the newly introduced signed Frontier-specific extrinsic for `pallet-ethereum`, a large part of transaction validation logic was only called in transaction pool validation, but not in block execution. Malicious validators can take advantage of this to put invalid transactions into a block. The attack is limited in that the signature is always validated, and the majority of the validation is done again in the subsequent `pallet-evm` execution logic. However, do note that a chain ID replay attack was possible. In addition, spamming attacks are of main concerns, while they are limited by Substrate block size limits and other factors. The issue is patched in commit `146bb48849e5393004be5c88beefe76fdf009aba`.

Category

5.3
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.57%
Third-Party Advisory github.com Third-Party Advisory github.com Third-Party Advisory github.com
Affected: paritytech frontier
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2021-41138?
CVE-2021-41138 has been scored as a medium severity vulnerability.
How to fix CVE-2021-41138?
To fix CVE-2021-41138, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-41138 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-41138 is being actively exploited. According to its EPSS score, there is a ~1% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-41138?
CVE-2021-41138 affects paritytech frontier.
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