CVE 2021-21779
A use-after-free vulnerability exists in the way Webkit’s GraphicsContext handles certain events in WebKitGTK 2.30.4. A specially crafted web page can lead to a potential information leak and further memory corruption. A victim must be tricked into visiting a malicious web page to trigger this vulnerability.
See the 
CVE page on Mitre.org
for more details.
