Because of the blockchain's decentralized nature, data in the network is not editable, added, or deleted. So some people consider blockchain a super safe software. However, in some respects, blockchain is less secure than other software.
Because the market is young, blockchain is even more vulnerable to attack than other software. There are thousands of blockchain, each with a different errorchain. Until the user selects some of the favorite blockchains as they did with the web browser, securing them would be a challenge.