A cross-site request forgery flaw was found in etcd 3.3.1 and earlier. An attacker can set up a website that tries to send a POST request to the etcd server and modify a key. Adding a key is done with PUT so it is theoretically safe (canโt PUT from an HTML form or such) but POST allows creating in-order keys that an attacker can send.
bugzilla.redhat.com/show_bug.cgi?id=1552714
github.com/coreos/etcd/issues/9353
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