A .NET security vulnerability which affects LINQPad has been reported by Soroush Dalili from NCC Group.
It applies to all versions of LINQPad 5 prior to 5.35, and all versions of LINQPad 4 prior to 4.59.
The vulnerabilities are fixed in the latest LINQPad builds (5.35 and 4.59), available for download. These will be rolled out as automatic updates shortly.
More information will be made available after NCC Group publishes the exploit. The scenarios for exploiting the vulnerability usefully are narrow.