A ransomware attack has disrupted MuniOS, a key platform for the $4.3 trillion municipal-bond market, affecting state and local borrowers’ ability to post debt documents. This incident highlights the significant cybersecurity risks facing public finance infrastructure. The negative impact is the potential delay in financing for essential public projects and increased operational costs for borrowers. The positive aspect is that such events can serve as a wake-up call, prompting greater investment in cybersecurity measures across the municipal sector. Investors in municipal bonds should be aware of these risks, as disruptions can impact the liquidity and reliability of the market. Robust cybersecurity protocols are essential for maintaining confidence in public finance.