CVE-2026-43427 usb: class: cdc-wdm: fix reordering issue in read code path
A race condition in the Linux kernel cdc-wdm driver allows attackers to read uninitialized memory via out-of-order execution.
- 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-2026-43427?
CVE-2026-43427 is a high-severity vulnerability in Linux kernel, published on 8 May 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:
usb: class: cdc-wdm: fix reordering issue in read code path
Quoting the bug report:
Due to compiler optimization or CPU out-of-order execution, the desc->length update can be reordered before the memmove. If this happens, wdm_read() can see the new length and call copy_to_user() on uninitialized memory. This also violates LKMM data race rules [1].
Fix it by using WRITE_ONCE and memory barriers.
Weakness: CWE-125
Which versions are affected by CVE-2026-43427?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43427?
Apply the vendor's patch.
Is CVE-2026-43427 being exploited?
There is no known exploitation of CVE-2026-43427 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-43427, DEBIAN-CVE-2026-43427, GHSA-jmm4-crvj-m7gx, ROOT-OS-DEBIAN-11-CVE-2026-43427, ROOT-OS-UBUNTU-2204-CVE-2026-43427, ROOT-OS-UBUNTU-2404-CVE-2026-43427 and 1 more.