In the Linux kernel, the following vulnerability has been resolved: net: wwan: mhi_wwan_mbim: guard against a cyclic NDP chain The NDP traversal in mhi_mbim_rx() only stops when wNextNdpIndex is zero

Overview

In the Linux kernel, the following vulnerability has been resolved:

net: wwan: mhi_wwan_mbim: guard against a cyclic NDP chain

The NDP traversal in mhi_mbim_rx() only stops when wNextNdpIndex is zero. Nothing requires the offsets to advance, so a modem that points an NDP at itself, or at an earlier NDP, keeps the loop spinning forever on one CPU.

Break out when the next NDP offset is not larger than the current one.

Verified in a QEMU guest with a fault injector feeding the driver's receive callback an NTB whose single NDP points at itself: the unpatched driver spins in mhi_mbim_rx() with one CPU pinned at 100% and the thread never returns. With this check the loop terminates within one iteration.

Changes in v2: move the non-increasing check to the wNextNdpIndex retrieval site, as suggested by Loic Poulain, instead of tracking the previous offset in a separate variable.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

Vendor advisories

• Red Hat VEX · Low · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-10-18 · vex