CVE-2026-74635

A flaw was found in the Linux kernel's fbdev subsystem, specifically within the bit_cursor() function. A local user can exploit this vulnerability by writing arbitrary values to the /dev/vcsa device or by manipulating font changes. This improper handling of glyph indices can lead to an out-of-bounds read, potentially resulting in information disclosure or a denial of service.

This vulnerability is rated as Moderate severity because exploitation requires local access with permissions to manipulate virtual console memory devices or adjust console fonts, restricting the primary impact to a system crash or out-of-bounds memory read. Standard server environments running headless or restricting virtual console device access face significantly lower exposure. Exploitation cannot occur remotely, and the flaw does not facilitate arbitrary code execution.

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.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.