selinux_edit_copy_tfiles in sudoedit in Sudo before 1.9.5 allows a local unprivileged user to gain file ownership and escalate privileges by replacing a temporary file with a symlink to an arbitrary file target. This affects SELinux RBAC support in permissive mode. Machines without SELinux are not vulnerable.

References

• https://nvd.nist.gov/vuln/detail/CVE-2021-23240
• https://bugzilla.suse.com/show_bug.cgi?id=CVE-2021-23240
• https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b@%3Cissues.bookkeeper.apache.org%3E
• https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4@%3Cissues.bookkeeper.apache.org%3E
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/EE42Y35SMJOLONAIBNYNFC7J44UUZ2Y6/
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GMY4VSSBIND7VAYSN6T7XIWJRWG4GBB3/
• https://security.gentoo.org/glsa/202101-33
• https://security.netapp.com/advisory/ntap-20210129-0010/
• https://www.sudo.ws/stable.html#1.9.5