CVE-2025-40322
Description
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.
Statement
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.
Mitigation
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.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.1 | N/A | 7.1 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
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