CVE-2025-40322

A flaw was found in the Linux kernel. A local attacker can exploit this vulnerability by providing a specially crafted font glyph index to the bitblit component. This can lead to an out-of-bounds read, potentially resulting in information disclosure or a denial of service.

This vulnerability is rated Moderate because it requires an authenticated local user with access to render text to the framebuffer console, and successful exploitation is limited to information disclosure or causing a system crash rather than arbitrary code execution. On typical Red Hat Enterprise Linux server deployments, systems operate headless or without active graphical framebuffer consoles, substantially reducing real-world exposure. The flaw cannot be exploited remotely without an established local access vector.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, prevent the fbdev kernel module from loading if it is not required for system operation. Create a file named /etc/modprobe.d/disable-fbdev.conf with the following content:

install fbdev /bin/true
blacklist fbdev

After creating the file, regenerate the initramfs using dracut -f -v and reboot the system for the changes to take effect. This mitigation may impact systems that rely on fbdev for console display or specific graphics hardware, requiring careful evaluation before implementation.