There is 1 open security issue in bookworm.
1 important issue:
A remote denial-of-service vulnerability exists in the way the Nouveau Display Driver (the default Ubuntu Nvidia display driver) handles GPU shader execution. A specially crafted pixel shader can cause remote denial-of-service issues. An attacker can provide a specially crafted website to trigger this vulnerability. This vulnerability can be triggered remotely after the user visits a malformed website. No further user interaction is required. Vulnerable versions include Ubuntu 18.04 LTS (linux 4.15.0-29-generic x86_64), Nouveau Display Driver NV117 (vermagic: 4.15.0-29-generic SMP mod_unload).