CVE-2026-98237 net: wwan: mhi_wwan_mbim: guard against a cyclic NDP chain
A malicious modem can cause a denial of service in the Linux kernel by sending a cyclic NDP chain, leading to an infinite loop and CPU exhaustion.
- 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-2026-98237?
CVE-2026-98237 is a denial of service vulnerability in Linux, published on 6 Oct 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:
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.
Which versions are affected by CVE-2026-98237?
How do I fix CVE-2026-98237?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-98237 being exploited?
There is no known exploitation of CVE-2026-98237 in the wild and no public exploit code.
Sources
Also known as AZL-106119, BELL-CVE-2026-98237, DEBIAN-CVE-2026-98237, GHSA-p39v-8ggf-chvp, UBUNTU-CVE-2026-98237.