CVE-2023-23586 Information

Description

Due to a vulnerability in the io_uring subsystem it is possible to leak kernel memory information to the user process. timens_install calls current_is_single_threaded to determine if the current process is single-threaded but this call does not consider io_uring’s io_worker threads thus it is possible to insert a time namespace’s vvar page to process’s memory space via a page fault. When this time namespace is destroyed the vvar page is also freed but not removed from the process’ memory and a next page allocated by the kernel will be still available from the user-space process and can leak memory contents via this (read-only) use-after-free vulnerability. We recommend upgrading past version 5.10.161 or commit 788d0824269bef539fe31a785b1517882eafed93 https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/io_uring

Reference

https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/io_uring?h=linux-5.10.y&id=788d0824269bef539fe31a785b1517882eafed93 https://kernel.dance/#788d0824269bef539fe31a785b1517882eafed93