  With the increasing popularity of cryptocurrencies and blockchain technology,
smart contracts have become a prominent feature in developing decentralized
applications. However, these smart contracts are susceptible to vulnerabilities
that hackers can exploit, resulting in significant financial losses. In
response to this growing concern, various initiatives have emerged. Notably,
the SWC vulnerability list played an important role in raising awareness and
understanding of smart contract weaknesses. However, the SWC list lacks
maintenance and has not been updated with new vulnerabilities since 2020. To
address this gap, this paper introduces the Smart Contract Weakness Enumeration
(SWE), a comprehensive and practical vulnerability list up until 2023. We
collect 273 vulnerability descriptions from 86 top conference papers and
journal papers, employing open card sorting techniques to deduplicate and
categorize these descriptions. This process results in the identification of 40
common contract weaknesses, which are further classified into 20 sub-research
fields through thorough discussion and analysis. SWE provides a systematic and
comprehensive list of smart contract vulnerabilities, covering existing and
emerging vulnerabilities in the last few years. Moreover, SWE is a scalable,
continuously iterative program. We propose two update mechanisms for the
maintenance of SWE. Regular updates involve the inclusion of new
vulnerabilities from future top papers, while irregular updates enable
individuals to report new weaknesses for review and potential addition to SWE.
