Tracked as CVE-2021-3156, a heap overflow bug found in sudo and dubbed “Baron Samedit” has been found recently. It allows an unprivileged user to gain root privileges on a vulnerable machine using a default sudo configuration.
The vulnerability itself has been hiding in plain sight for nearly 10 years. It was introduced in July 2011 (commit 8255ed69) and affects all legacy versions from 1.8.2 to 1.8.31p2 and all stable versions from 1.9.0 to 1.9.5p1 in their default configuration.
2020-02-03: Looks like macOS is affected after all.
Check It Out: Buffer Overflow Bug Found in SUDO Dubbed ‘Baron Samedit’