CVE-2021-21405

CVE-2021-21405 describes a critical vulnerability in Lotus, an implementation of the Filecoin protocol. The flaw stems from the BLS signature validation process, which allowed for two distinct CIDs for a single valid block, potentially enabling malicious actors to punish miners for legitimate blocks. This vulnerability carries a CVSSv3 score of 7.5 (High), indicating a network-based attack with low complexity and a high impact on integrity. There is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.