# CVE-2026-98860: HID: bpf: cast size to ssize_t when checking hid_bpf_hw_request

> A type confusion in the Linux kernel HID BPF subsystem allows hardware errors to be misinterpreted as success, potentially exposing uninitialized memory to BPF programs.

- **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:** 18 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-98860, DEBIAN-CVE-2026-98860, GHSA-243p-r44x-jh77, UBUNTU-CVE-2026-98860

## What is CVE-2026-98860?

CVE-2026-98860 is a vulnerability in Linux, published on 18 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:

HID: bpf: cast size to ssize_t when checking hid_bpf_hw_request

As reported by Sashiko:
If a transport driver encounters a hardware error and returns a negative
error code such as -EPIPE, ret is implicitly promoted to size_t when
compared against size. This causes the negative error code to evaluate
as a large positive number, making the (ret > size) condition true.

This silently converts the hardware error into a success return value
and copies the unmodified buffer back, which could leave BPF programs
operating on uninitialized or stale data.

Fix this by casting size into ssize_t to return the actual negative
error code.

## Which versions are affected by CVE-2026-98860?


## How do I fix CVE-2026-98860?

Apply the vendor's patch.

## Is CVE-2026-98860 being exploited?

There is no known exploitation of CVE-2026-98860 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98860 and fix it if it is affected.

What it is: CVE-2026-98860 is a vulnerability in Linux, published on 18 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-2026-98860 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-2026-98860/ (Markdown: https://insights.sbomify.com/CVE-2026-98860/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98860
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98860
- OSV: https://osv.dev/vulnerability/CVE-2026-98860

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98860/
Summaries are generated and may contain mistakes; the official description above is the record.