We had one significant vulnerability pretty early on: https://blog.boltz.exchange/p/the-problem-with-free-options-69f9f59a2d48. But it was never user funds at risk. Just ours :/ Nothing in recent years.

Downtimes: many. Scroll through our twitter and you'll see the pain we went through. Mostly caused by either crashes of our LND e.g. https://nitter.net/Boltzhq/status/1666434127321522185 or planned restarts of our LND node to do the necessary db compaction. Most significant down time in recent history was back in May because we were unprepared for the fee hike see https://nitter.net/Boltzhq/status/1656013583124242437.

We have learned from this a ton, worked a lot to prevent both from causing significant down time again in the future (second CLN node as failover see #339248, also huge work went into automating our liquidity management) and things look a lot better now.