TL;DR: Principal maintainer of the GnuPG FAQ, Robert J. Hansen, recently disclosed “unknown actors deployed a certificate spamming attack against two high-profile contributors in the OpenPGP community,” namely himself and Daniel Kahn Gillmor. Fearing mitigation to be too far off, he advised users “stop retrieving data from the SKS keyserver network.”
https://coinspice.io/news/openpgp-spam-attack-poisoned-certs-already-on-sks-keyserver-network/