This post presents the disclosure process of a subtle issue in the Cairo VM which was discovered during the Starknet OS audit. The transaction execution in SN is done in 2 phases: Sequencing and proving. During a Starknet OS audit done by @fcremo from @Zellic_io a concern was raised that one of the Cairo opcodes may be unsafe. We conducted a thorough investigation and ruled out the safety concern that was initially raised. However, we did find a potential inconsistency between the checks done...| Starknet Community Forum