Chompie (https://twitter.com/chompie1337) does a great job on exploit writeups. Take a look at https://www.graplsecurity.com/post/iou-ring-exploiting-the-l.... She's got a few more blog posts at Grapl, but she's moved on to new things at xforcered at IBM.

Darknet Diaries isn't terribly technical, but has some good history.

https://schneier.com

https://krebsonsecurity.com

https://reddit.com/r/netsec has a lot of good technical material posted

Start with tldrsec.com - then accumulate blogs from the included links