# CVE-2026-80783: HID: magicmouse: prevent unbounded recursion in magicmouse_raw_event()

> A malicious HID device can cause a kernel stack overflow and system crash by sending crafted reports to the magicmouse driver.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 4 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-99492, BELL-CVE-2026-80783, DEBIAN-CVE-2026-80783, GHSA-846j-3r8r-8xv8, UBUNTU-CVE-2026-80783

## What is CVE-2026-80783?

CVE-2026-80783 is a denial of service vulnerability in Linux, published on 4 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

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

HID: magicmouse: prevent unbounded recursion in magicmouse_raw_event()

magicmouse_raw_event() handles DOUBLE_REPORT_ID (0xf7) packets, which pack
two touch reports into one, by splitting the packet and calling itself on
each half. The only guard against runaway recursion is a "size < 1" check,
which stops zero-sized calls but does not bound the recursion depth.

A malicious HID device that matches this driver can send a report starting
with DOUBLE_REPORT_ID and filled with the sequence [0xf7, 0x00]. Each level
consumes two bytes and recurses on the remainder, so an incoming report of
up to HID_MAX_BUFFER_SIZE (16 KiB) drives roughly 8000 nested calls. That
easily exhausts the 16 KiB kernel stack, leading to a stack overflow: a
panic with CONFIG_VMAP_STACK, or memory corruption without it.

A double report only ever wraps two normal reports; it is never
legitimately nested. Refuse to re-enter the DOUBLE_REPORT_ID case from a
recursive call so the recursion depth is bounded to two, while all valid
packets keep being parsed exactly as before.

## Which versions are affected by CVE-2026-80783?


## How do I fix CVE-2026-80783?

Apply the vendor's patch.

## Is CVE-2026-80783 being exploited?

There is no known exploitation of CVE-2026-80783 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80783 and fix it if it is affected.

What it is: CVE-2026-80783 is a denial of service vulnerability in Linux, published on 4 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-80783 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-2026-80783/ (Markdown: https://insights.sbomify.com/CVE-2026-80783/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80783
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80783
- OSV: https://osv.dev/vulnerability/CVE-2026-80783

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80783/
Summaries are generated and may contain mistakes; the official description above is the record.