A flaw was found in xorg-x11-server in versions before 21.1.2 and before 1.20.14. An out-of-bounds access can occur in the SwapCreateRegister function. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
https://www.zerodayinitiative.com/advisories/ZDI-21-1550/
https://www.debian.org/security/2021/dsa-5027
https://security.netapp.com/advisory/ntap-20220114-0004/
https://security.gentoo.org/glsa/202305-30
https://lists.x.org/archives/xorg-announce/2021-December/003124.html
https://lists.x.org/archives/xorg-announce/2021-December/003122.html
https://lists.debian.org/debian-lts-announce/2021/12/msg00035.html