What are the weaknesses of Solana?

When it comes to the weaknesses of Solana, there are a few key areas that I'm particularly interested in. Could you elaborate on the scalability challenges Solana has faced? Have there been any notable instances where the network's performance has been significantly impacted? Additionally, I'm curious about the security vulnerabilities that have been identified in Solana's codebase. Have these been effectively addressed, or are they still posing a significant risk? Furthermore, I'm also wondering about the competition in the crypto space. How does Solana stack up against other blockchains in terms of features, transaction speed, and cost? It would be great to get a comprehensive overview of these weaknesses to better understand the challenges facing Solana.