CVE-2025-68308 can: kvaser_usb: leaf: Fix potential infinite loop in command parsers
A flaw in the Kvaser USB CAN driver allows a local attacker to cause a system hang via an infinite loop when processing specific USB data.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-68308?
CVE-2025-68308 is a denial of service vulnerability in Linux, published on 16 Dec 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:
can: kvaser_usb: leaf: Fix potential infinite loop in command parsers
The `kvaser_usb_leaf_wait_cmd()` and `kvaser_usb_leaf_read_bulk_callback` functions contain logic to zero-length commands. These commands are used to align data to the USB endpoint's wMaxPacketSize boundary.
The driver attempts to skip these placeholders by aligning the buffer position `pos` to the next packet boundary using `round_up()` function.
However, if zero-length command is found exactly on a packet boundary (i.e., `pos` is a multiple of wMaxPacketSize, including 0), `round_up` function will return the unchanged value of `pos`. This prevents `pos` to be increased, causing an infinite loop in the parsing logic.
This patch fixes this in the function by using `pos + 1` instead. This ensures that even if `pos` is on a boundary, the calculation is based on `pos + 1`, forcing `round_up()` to always return the next aligned boundary.
Which versions are affected by CVE-2025-68308?
How do I fix CVE-2025-68308?
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-2025-68308 being exploited?
There is no known exploitation of CVE-2025-68308 in the wild and no public exploit code.
Sources
Also known as AZL-72661, BELL-CVE-2025-68308, DEBIAN-CVE-2025-68308, GHSA-qxh5-h6mx-qv45, ROOT-OS-UBUNTU-2204-CVE-2025-68308, ROOT-OS-UBUNTU-2404-CVE-2025-68308 and 1 more.