On: Ask HN: Did you encounter any leap year bugs today...

[jonathantf2]

Our Sophos anti-virus at work blocked access to every website this morning because of the leap year, had to disable the web filtering to get us back up and running.

[fostware → jonathantf2]

Yeah, so many "untrusted website" screenshots in the office chat. Half a productive day for staff in Australia

[mcpherrinm → jonathantf2]

Does anyone affected have a copy of one of the affected certificates? I'd be interested in seeing more detail on what went wrong.

The most likely thing to me would be that it attempted to issue a 1-year-long certificate, but naively produced a date of Feb 29, 2025.

Dates in certificates are encoded as `YYMMDDhhmmssZ` so it would certainly be possible to produce a certificate with an invalid date.