The Xen Project has published Xen Security Advisories 313, 314, 316, and 318 (XSA-313, XSA-314, XSA-316, and XSA-318, respectively). These XSAs do not affect the security of Qubes OS, and no user action is necessary.
This is a companion discussion topic for the original entry at https://www.qubes-os.org/news/2020/04/15/xsa-313-314-316-318-qubes-not-affected/