CVE-2025-21742 usbnet: ipheth: use static NDP16 location in URB

High 7.1 Published 27 Feb 2025 Updated 11 May 2026

A flaw in the Linux kernel's ipheth driver allows out-of-bounds reads via crafted USB network packets, potentially leading to information disclosure or crashes.

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-2025-21742?

CVE-2025-21742 is a high-severity memory corruption vulnerability in Linux kernel, published on 27 Feb 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:

usbnet: ipheth: use static NDP16 location in URB

Original code allowed for the start of NDP16 to be anywhere within the URB based on the `wNdpIndex` value in NTH16. Only the start position of NDP16 was checked, so it was possible for even the fixed-length part of NDP16 to extend past the end of URB, leading to an out-of-bounds read.

On iOS devices, the NDP16 header always directly follows NTH16. Rely on and check for this specific format.

This, along with NCM-specific minimal URB length check that already exists, will ensure that the fixed-length part of NDP16 plus a set amount of DPEs fit within the URB.

Note that this commit alone does not fully address the OoB read. The limit on the amount of DPEs needs to be enforced separately.

Weakness: CWE-125

Which versions are affected by CVE-2025-21742?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2025-21742?

Apply the vendor's patch.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2025-21742 being exploited?

There is no known exploitation of CVE-2025-21742 in the wild and no public exploit code.

All Linux kernel vulnerabilities

Sources

Also known as BELL-CVE-2025-21742, DEBIAN-CVE-2025-21742, GHSA-xg22-883p-m58m, ROOT-OS-UBUNTU-2404-CVE-2025-21742, UBUNTU-CVE-2025-21742.