CVE-2025-38198 fbcon: Make sure modelist not set on unregistered console
A local attacker can trigger a kernel crash by writing to a sysfs node when a console is unregistered, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-38198?
CVE-2025-38198 is a high-severity vulnerability in Debian Debian Linux, published on 4 Jul 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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 callers of fbcon_info_from_console() are trying to compare against existing "info" pointers, so error handling should kick in correctly.
Weakness: CWE-129
Which versions are affected by CVE-2025-38198?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-38198?
Apply the vendor's patch.
Is CVE-2025-38198 being exploited?
There is no known exploitation of CVE-2025-38198 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as AZL-64662, AZL-72769, BELL-CVE-2025-38198, DEBIAN-CVE-2025-38198, GHSA-2v92-8hh5-248m, ROOT-OS-DEBIAN-11-CVE-2025-38198 and 4 more.