If exploited, these flaws can allow attackers to gain unauthorized access to sensitive information or generally cause problems
The kernel of Linux 6.3 was released just under 2 months ago and of which the launch of the 6.4 branch is also expected in the coming weeks.
Within Linux 6.3 most notable changes it was cleanup of outdated ARM platforms and graphics drivers, continuous integration of Rust language support, hwnoise utility, among other things.
Mentioning this version of the Linux Kernel is due to the fact that it is currently the stable branch and on which various corrective versions have been released. With this we could think that the errors detected/reported and solved are implemented immediately, a situation that is not always the case.
Linux 6.3 triggers post-release usage within #nouveau with the consequence of kernel memory corruption.
If you're running 6.3 and # nouveau , it's best to downgrade to 6.2 if you don't want to risk messing up your filesystem or causing any other abnormal behavior.
And it is that recently Red Hat's Karol Herbst, who is involved in the development of Mesa, the Nouveau driver and the OpenCL open stack, I detect an error that causes a crash due to kernel memory corruption as a result of code accessing an already freed (use after free) memory area.
As such advised users of open source drivers for NVIDIA graphics cards to refrain from using the Linux 6.3 kernel due to the specific bug in the nouveau driver code.
In addition to this, it is also mentioned that the bug can also be used as a vulnerability to elevate one's privileges on the system, but the possibility of creating an exploit has not yet been confirmed. It is also not excluded that the failure that occurs may lead to a violation of the integrity of the file system, since, in theory, kernel memory corruption can affect the areas in which ext4 file system structures are stored. .
So far the problem has been resolved only in patch form, which has not yet been accepted in the kernel.
Another of the mistakesue have been detected in the Linux 6.3 kernel (late April) revealed a bug that corrupted the XFS file system metadata.
The problem is not fully fixed yet and manifests itself in update 6.3.4, among other things (the corruption was fixed in versions 6.3.1, 6.3.2, 6.3.3 and 6.3.4, but the manifestation of the problem is in question in version 6.3.0).
In previous kernel branches, such as 6.2, as well as the 6.4 branch that is in development, the manifestation of the problem is not fixed. The change that caused the problem and the exact factors that caused the error have not yet been determined.
Last but not least, It is also worth mentioning the recent vulnerability (already listed under CVE-2023-3138) in the libx11 library developed by the X.Org project, which offers functions with a client implementation of the X11 protocol, which leads to memory corruption in a client application if it connects to a malicious X Server or attacker-controlled intermediate proxy.
About the problem, it is mentioned that it is present in the file InitExt.c and is due to a lack of validation of the values passed by the X server for the request, event, and error IDs before using them as an index of the array element being written to.
According to preliminary estimates, since the size of the identifier field is limited to one byte, the vulnerability can only be used to rewrite parts of the display structure without going beyond its limits, i.e. limited to process termination. .
It is worth mentioning that the problem was fixed in libX11 version 1.8.6 and users are encouraged to make relevant updates.
Finally if you are interested in knowing more about it about the mentioned failures, you can check the details in the following links.
- nouveau vulnerability: https://lists.freedesktop.org
- XFS issues: https://bugzilla.redhat.com
- Vulnerability in libX11: https://www.mail-archive.com/
That is why it is not good to be up to date in everything.