CVE-2025-38198

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

fbcon: Make sure modelist not set on unregistered console

It looks like attempting to write to the "store_modes" sysfs node will

run afoul of unregistered consoles:

UBSAN: array-index-out-of-bounds in drivers/video/fbdev/core/fbcon.c:122:28

index -1 is out of range for type 'fb_info *[32]'

...

fbcon_info_from_console+0x192/0x1a0 drivers/video/fbdev/core/fbcon.c:122

fbcon_new_modelist+0xbf/0x2d0 drivers/video/fbdev/core/fbcon.c:3048

fb_new_modelist+0x328/0x440 drivers/video/fbdev/core/fbmem.c:673

store_modes+0x1c9/0x3e0 drivers/video/fbdev/core/fbsysfs.c:113

dev_attr_store+0x55/0x80 drivers/base/core.c:2439

static struct fb_info *fbcon_registered_fb[FB_MAX];

...

static signed char con2fb_map[MAX_NR_CONSOLES];

...

static struct fb_info *fbcon_info_from_console(int console)

...

return fbcon_registered_fb[con2fb_map[console]];

If con2fb_map contains a -1 things go wrong here. Instead, return NULL,

as call

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References