CVE-2022-39242: 
Rust vulnerability analysis and mitigation

A vulnerability was discovered in Frontier (Rust) package affecting versions prior to commit d3beddc6911a559a3ecc9b3f08e153dbe37a8658. The issue relates to improper weight refunding after EVM execution, where the system was not correctly accounting for unused weights after transactions (GitHub Advisory).

The vulnerability stems from a bug where the worst-case weight (based on gaslimit) was being accounted for in all cases, without properly refunding weight after execution. The system failed to call Extra::postdispatch which should invoke CheckWeight::post_dispatch for proper weight refunding (GitHub PR).

The vulnerability could potentially lead to block spamming attacks where adversaries could construct blocks with transactions having large amounts of refunds or unused gases with reverts, potentially inflating chain gas prices. However, the impact was limited as any spamming attack would still be costly for adversaries and couldn't alter chain state (GitHub Advisory).

The vulnerability was patched in commit d3beddc6911a559a3ecc9b3f08e153dbe37a8658 through PR #851, which implemented proper weight refunding after EVM execution. No workarounds were available before the patch (GitHub Advisory).