A type confusion issue was addressed with improved state handling. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, tvOS 14.4, watchOS 7.3, iOS 14.4 and iPadOS 14.4, Safari 14.0.3. Processing maliciously crafted web content may lead to arbitrary code execution.

This issue was addressed with improved iframe sandbox enforcement. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave. Maliciously crafted web content may violate iframe sandboxing policy.

"Clear History and Website Data" did not clear the history. The issue was addressed with improved data deletion. This issue is fixed in macOS Big Sur 11.1, Security Update 2020-001 Catalina, Security Update 2020-007 Mojave, iOS 14.3 and iPadOS 14.3, tvOS 14.3. A user may be unable to fully delete browsing history.

The bubblewrap sandbox of WebKitGTK and WPE WebKit, prior to 2.28.3, failed to properly block access to CLONE_NEWUSER and the TIOCSTI ioctl. CLONE_NEWUSER could potentially be used to confuse xdg-desktop-portal, which allows access outside the sandbox. TIOCSTI can be used to directly execute commands outside the sandbox by writing to the controlling terminal's input buffer, similar to CVE-2017-5226.

A use-after-free issue exists in WebKitGTK before 2.28.1 and WPE WebKit before 2.28.1 via crafted web content that allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash).

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.

A logic issue was addressed with improved state management. This issue is fixed in iOS 13.3.1 and iPadOS 13.3.1, tvOS 13.3.1, Safari 13.0.5, iTunes for Windows 12.10.4, iCloud for Windows 11.0, iCloud for Windows 7.17. Processing maliciously crafted web content may lead to universal cross site scripting.

Webkit-GTK 2.x (any version with HTML5 audio/video support based on GStreamer) allows remote attackers to trigger unexpectedly high sound volume via malicious javascript. NOTE: this WebKit-GTK behavior complies with existing W3C standards and existing practices for GNOME desktop integration.

A logic issue was addressed with improved state management. This issue is fixed in iOS 13, Safari 13. Processing maliciously crafted web content may lead to universal cross site scripting.

WebKitGTK and WPE WebKit prior to version 2.24.1 failed to properly apply configured HTTP proxy settings when downloading livestream video (HLS, DASH, or Smooth Streaming), an error resulting in deanonymization. This issue was corrected by changing the way livestreams are downloaded.

The UIProcess subsystem in WebKit, as used in WebKitGTK through 2.23.90 and WebKitGTK+ through 2.22.6 and other products, does not prevent the script dialog size from exceeding the web view size, which allows remote attackers to cause a denial of service (Buffer Overflow) or possibly have unspecified other impact, related to UIProcess/API/gtk/WebKitScriptDialogGtk.cpp, UIProcess/API/gtk/WebKitScriptDialogImpl.cpp, and UIProcess/API/gtk/WebKitWebViewGtk.cpp, as demonstrated by GNOME Web (aka Epiphany).

WebKitGTK and WPE WebKit prior to version 2.24.1 are vulnerable to address bar spoofing upon certain JavaScript redirections. An attacker could cause malicious web content to be displayed as if for a trusted URI. This is similar to the CVE-2018-8383 issue in Microsoft Edge.