CVE-2023-54277 fbdev: udlfb: Fix endpoint check
A missing endpoint type check in the udlfb driver allows a malicious USB device to trigger a kernel warning and potential denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2023-54277?
CVE-2023-54277 is a denial of service vulnerability in Linux, published on 30 Dec 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
In the Linux kernel, the following vulnerability has been resolved:
fbdev: udlfb: Fix endpoint check
The syzbot fuzzer detected a problem in the udlfb driver, caused by an endpoint not having the expected type:
usb 1-1: Read EDID byte 0 failed: -71 usb 1-1: Unable to get valid EDID from device/display ------------[ cut here ]------------ usb 1-1: BOGUS urb xfer, pipe 3 != type 1 WARNING: CPU: 0 PID: 9 at drivers/usb/core/urb.c:504 usb_submit_urb+0xed6/0x1880 drivers/usb/core/urb.c:504 Modules linked in: CPU: 0 PID: 9 Comm: kworker/0:1 Not tainted 6.4.0-rc1-syzkaller-00016-ga4422ff22142 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023 Workqueue: usb_hub_wq hub_event RIP: 0010:usb_submit_urb+0xed6/0x1880 drivers/usb/core/urb.c:504 ... Call Trace: <TASK> dlfb_submit_urb+0x92/0x180 drivers/video/fbdev/udlfb.c:1980 dlfb_set_video_mode+0x21f0/0x2950 drivers/video/fbdev/udlfb.c:315 dlfb_ops_set_par+0x2a7/0x8d0 drivers/video/fbdev/udlfb.c:1111 dlfb_usb_probe+0x149a/0x2710 drivers/video/fbdev/udlfb.c:1743
The current approach for this issue failed to catch the problem because it only checks for the existence of a bulk-OUT endpoint; it doesn't check whether this endpoint is the one that the driver will actually use.
We can fix the problem by instead checking that the endpoint used by the driver does exist and is bulk-OUT.
Which versions are affected by CVE-2023-54277?
How do I fix CVE-2023-54277?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2023-54277 being exploited?
There is no known exploitation of CVE-2023-54277 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2023-54277, DEBIAN-CVE-2023-54277, GHSA-gqhr-h84m-5956, UBUNTU-CVE-2023-54277.