CVE-2026-74456 can: peak_usb: peak_usb_start(): fix double free of transfer buffer on URB submit error
A double free vulnerability in the Linux kernel peak_usb driver allows attackers to cause denial of service or potentially execute code via URB submit errors.
- 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-2026-74456?
CVE-2026-74456 is a high-severity use after free vulnerability in Linux, published on 15 Aug 2026. 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: peak_usb: peak_usb_start(): fix double free of transfer buffer on URB submit error
In peak_usb_start(), each RX URB transfer buffer is allocated with kmalloc() and the URB is flagged URB_FREE_BUFFER so that the final usb_free_urb() also frees the transfer buffer.
If usb_submit_urb() fails, the error path frees the buffer explicitly with kfree(buf) and then calls usb_free_urb(urb). Because URB_FREE_BUFFER is set, usb_free_urb() -> urb_destroy() frees the same buffer a second time, a double free of the transfer buffer.
BUG: KASAN: double-free in usb_free_urb.part.0+0x91/0xb0 Free of addr ffff8881069ccb80 by task trigger.sh/285
Call Trace: kfree+0x113/0x3c0 usb_free_urb.part.0+0x91/0xb0
Drop the redundant kfree(buf); usb_free_urb() already releases the transfer buffer. This mirrors commit 03819abbeb11 ("net: usb: lan78xx: Fix double free issue with interrupt buffer allocation").
Which versions are affected by CVE-2026-74456?
How do I fix CVE-2026-74456?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-74456 being exploited?
There is no known exploitation of CVE-2026-74456 in the wild and no public exploit code.
Sources
Also known as AZL-96012, BELL-CVE-2026-74456, DEBIAN-CVE-2026-74456, GHSA-crgv-x77w-rh88, UBUNTU-CVE-2026-74456.