# 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.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-106119, BELL-CVE-2026-98237, DEBIAN-CVE-2026-98237, GHSA-p39v-8ggf-chvp, UBUNTU-CVE-2026-98237

## 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.

## Is CVE-2026-98237 being exploited?

There is no known exploitation of CVE-2026-98237 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98237 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-98237 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-98237/ (Markdown: https://insights.sbomify.com/CVE-2026-98237/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98237
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98237
- OSV: https://osv.dev/vulnerability/CVE-2026-98237

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98237/
Summaries are generated and may contain mistakes; the official description above is the record.