Mickael Karatekin discovered that the GNOME session locking didn't restrict a keyboard shortcut used for taking screenshots in GNOME Screenshot which could result in information disclosure.
The oldstable distribution (bullseye) is not affected.
For the stable distribution (bookworm), this problem has been fixed in version 43.6-1~deb12u2.
We recommend that you upgrade your gnome-shell packages.
For the detailed security status of gnome-shell please refer to its security tracker page at: \ https://security-tracker.debian.org/tracker/gnome-shell