Good find, Dave.
Linux is not the perfect safe haven it is thought to be....there are people working away in the background, discovering things like this which will bring Linux/Ubuntu/Fedora/Debian OS's unstuck if care is not taken, particularly regarding the timely download and install of security updates.
To be clear, an 'exploit' such as this gives a remote intruder access to root privileges on default installations of Debian 12 and 13, Ubuntu 22.04 and 23.04, and Fedora 37 and 38
Gaining Root privileges means they can do whatever they like on those systems
?? Is your system fully updated ??
The bug appears to have been discovered by a research company who research these matters among other things, so there doesn't appear to be any use of the exploit which has caused a problem for linux users. It's been fixed upstream, so updating will resolve the issue.
At the bottom of this page:
https://www.helpnetsecurity.com/2023/10/05/cve-2023-4911/
one can select links to the following distros: Ubuntu, RedHat, Debian, Fedora, Gentoo, where there is more information on the fixes and the versions of glibc that include the fixes in some cases.
Briefly, the info is as follows:
For the debian stable distribution (bookworm), this problem has been fixed in version 2.36-9+deb12u3.
For fedora looks like it needs glibc-2.38-6.fc39.
For Red Hat on its site, there's some code available, and a table to see the now unaffected versions.
For ubuntu 23.04, upgrade to libc6 - 2.37-0ubuntu2.1, and ubuntu 22.04, to libc6 - 2.35-0ubuntu3.4.