CVE-2026-74679 usb: gadget: f_ncm: Use unsigned int for ndp_index
A malicious USB host can trigger an integer overflow in the Linux kernel NCM gadget driver, leading to an out-of-bounds memory read.
- 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-2026-74679?
CVE-2026-74679 is a vulnerability in Linux, published on 22 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:
usb: gadget: f_ncm: Use unsigned int for ndp_index
The variable ndp_index is declared as a signed integer, but it stores the return value of get_ncm(), which is unsigned.
A malicious host can supply a large offset that overflows the signed ndp_index, making it negative. Because ndp_index is compared against unsigned bounds, this negative value bypasses sanity checks and leads to an out-of-bounds read when calculating the address of the NDP block (ntb_ptr + ndp_index).
Fix this by changing ndp_index to unsigned int to ensure consistent unsigned comparisons throughout the function.
Which versions are affected by CVE-2026-74679?
How do I fix CVE-2026-74679?
Apply the vendor's patch.
Is CVE-2026-74679 being exploited?
There is no known exploitation of CVE-2026-74679 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74679, DEBIAN-CVE-2026-74679, GHSA-6qhg-x625-34c5, UBUNTU-CVE-2026-74679.