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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-13753
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GER2ATKZXDHM7FFYJH67ZPNZZX5VOUVM/
• https://security.gentoo.org/glsa/202007-11
• https://trac.webkit.org/changeset/262368/webkit
• https://usn.ubuntu.com/4422-1/
• https://www.debian.org/security/2020/dsa-4724
• https://www.openwall.com/lists/oss-security/2020/07/10/1
• http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00074.html