CVE-2023-23586 Use after free in io_uring in the Linux Kernel
A use-after-free in the Linux kernel io_uring subsystem allows local attackers to leak kernel memory contents to user space.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-23586?
CVE-2023-23586 is a medium-severity use after free vulnerability in Linux kernel, published on 17 Feb 2023. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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
Weakness: CWE-416
Which versions are affected by CVE-2023-23586?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2023-23586?
Upgrade to a fixed version.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2023-23586 being exploited?
There is no known exploitation of CVE-2023-23586 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2023-23586, GHSA-h86q-32m7-8f9v, UBUNTU-CVE-2023-23586.