net/can/bcm.c in the Linux kernel through 5.12.10 allows local users to obtain sensitive information from kernel stack memory because parts of a data structure are uninitialized.
https://www.debian.org/security/2021/dsa-4941
https://lists.debian.org/debian-lts-announce/2021/07/msg00016.html
https://lists.debian.org/debian-lts-announce/2021/07/msg00015.html
https://lists.debian.org/debian-lts-announce/2021/07/msg00014.html