# CVE-2026-98236: net: wwan: mhi_wwan_mbim: check skb_copy_bits() return value

> A malicious modem can leak kernel heap memory into the network stack by providing invalid datagram offsets in the Linux kernel WWAN driver.

- **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-106221, BELL-CVE-2026-98236, DEBIAN-CVE-2026-98236, GHSA-f277-f268-9h2q, UBUNTU-CVE-2026-98236

## What is CVE-2026-98236?

CVE-2026-98236 is a 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: check skb_copy_bits() return value

mhi_mbim_rx() ignores the return value of skb_copy_bits() when it
copies each datagram out of the NTB.  The datagram offset and length
come from the DPE, which is only checked to lie within the NTB
itself, so a modem can point a datagram outside the received skb.
The copy then fails and the freshly allocated skbn is passed to
netif_rx() with its uninitialized contents still in place, leaking
kernel heap memory into the network stack.

Free the skb and account an error when the copy fails.

Verified in a QEMU guest with a fault injector pointing a DPE
outside the received NTB: the copy fails, and the unpatched driver
hands the uninitialized skbn to the network stack (observed as
"unknown protocol" on bytes that were never written).  With this
check the failed datagram is dropped and counted as an rx error.

Changes in v2: factor the free-and-count sequence out into
mhi_mbim_rx_drop(), shared with the unknown-protocol path, as
suggested by Loic Poulain.

## Which versions are affected by CVE-2026-98236?


## How do I fix CVE-2026-98236?

Apply the vendor's patch.

## Is CVE-2026-98236 being exploited?

There is no known exploitation of CVE-2026-98236 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98236 and fix it if it is affected.

What it is: CVE-2026-98236 is a 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-2026-98236 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-2026-98236/ (Markdown: https://insights.sbomify.com/CVE-2026-98236/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98236
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98236
- OSV: https://osv.dev/vulnerability/CVE-2026-98236

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98236/
Summaries are generated and may contain mistakes; the official description above is the record.