Press reports on monero privacy issues:

Monero Privacy Protections Aren’t as Strong as They Seem | WIRED 2018
https://www.wired.com/story/monero-privacy/

Monero [XMR] Privacy Protection May Be Deficient 2018
https://globalcoinreport.com/monero-xmrs-privacy-protection-may-be-deficient/

Monero has some real issues! 2018
https://news.ycombinator.com/item?id=16688416

Monero Transactions History Can Be Revealed and Exposed: Research
https://cointelegraph.com/news/monero-transactions-history-can-be-revealed-and-exposed-research

CryptoNote Currency Bug Allowed Creation of Unlimited Number of Coins
https://www.cryptocoinsnews.com/cryptonote-currency-bug-allowed-creation-unlimited-number-coins/

Warning: Every CryptoNote/Monero transaction in history will be retroactively exposed
https://steemit.com/cryptonote/@macrochip/warning-every-cryptonote-monero-transaction-in-history-will-be-retroactively-exposed

Fundamental monero security flaw, Chain Split attack...
What chain splits mean for Monero 2018

2017
A well-respected cryptographer earlier this year released a tool called http://www.monerolink.com, where you can link all transactions from 2014-2016 with 100% (due to blockchain timing analysis apparently), and all transactions from 2016-2017 are linkable with a probabilistic distribution dependent on mixin size. So they have a table on the site, 1 mixin transactions are linkable 86% of the time, 10+ mixin transactions are linkable 22% of the time. Monero has fixed this bug since January of this year, but if you used monero on a DNM between 2014-Jan 2017, BEWARE!