Oracle Linux: CVE-2019-18634: ELSA-2020-0540: sudo security update (IMPORTANT) (Multiple Advisories)

In Sudo before 1.8.26, if pwfeedback is enabled in /etc/sudoers, users can trigger a stack-based buffer overflow in the privileged sudo process. (pwfeedback is a default setting in Linux Mint and elementary OS; however, it is NOT the default for upstream and many other packages, and would exist only if enabled by an administrator.) The attacker needs to deliver a long string to the stdin of getln() in tgetpass.c.
A flaw was found in the Sudo application when the ’pwfeedback' option is set to true on the sudoers file. An authenticated user can use this vulnerability to trigger a stack-based buffer overflow under certain conditions even without Sudo privileges. The buffer overflow may allow an attacker to expose or corrupt memory information, crash the Sudo application, or possibly inject code to be run as a root user.