WebKitGTK through 2.26.4 and WPE WebKit through 2.26.4 (which are the versions right before 2.28.0) contains a memory corruption issue (use-after-free) that may lead to arbitrary code execution. This issue has been fixed in 2.28.0 with improved memory handling.
lists.opensuse.org/opensuse-security-announce/2020-05/msg00008.html
bugs.webkit.org/show_bug.cgi?id=204342#c21
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DOR5LPL4UASVAR76EIHCL4O2KGDWGC6K/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GLERWAS2LL7SX2GHA2DDZ2PL3QC5OHIF/
security.gentoo.org/glsa/202006-08
usn.ubuntu.com/4310-1/
webkitgtk.org/security/WSA-2020-0003.html
wpewebkit.org/security/WSA-2020-0003.html
www.debian.org/security/2020/dsa-4641