UPDATE 03/20/2018 – FULL REPORT HAS BEEN RELEASED. Some of the initial speculation regarding the exploit was correct and some was less so. If you have not updated to the latest firmware, go ahead and do so now.
Full report: https://saleemrashid.com/2018/03/20/breaking-ledger-security-model/
**Ledger has released a firmware update for the Nano S in response to the exploit described in the link.