AIKIDO-2026-160502
zebrad is vulnerable to Incorrect Calculation
37
Low Risk
This Affects:
zebradTL;DR
When building a block template Zebra's transaction selector budgets mempool transactions against the maximum block size but reserves space only for the coinbase transaction. It does not reserve space for the serialized block header or the transaction-count field, both of which count toward the maximum block size. A template can therefore be filled past the limit, so a solved block exceeds the consensus size and is rejected by every validating node, wasting the proof-of-work. The fix reserves the network-specific header size and maximum transaction-count width before admitting transactions.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and you mine using Zebra's block templates through getblocktemplate or the built-in miner.
Background info
zebrad is vulnerable to Incorrect Calculation in versions 0.0.1 - 6.0.0.
How to fix this
Upgrade the zebrad library to the patch version.
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SOC 2Compliant
ISO 27001Compliant