# CVE-2024-39509: HID: core: remove unnecessary WARN_ON() in implement()

> A local attacker can trigger a kernel warning via HID output reports, potentially causing system instability or denial of service.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 12 Jul 2024
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2024-39509, DEBIAN-CVE-2024-39509, GHSA-rp86-8ghx-v767, UBUNTU-CVE-2024-39509

## What is CVE-2024-39509?

CVE-2024-39509 is a medium-severity denial of service vulnerability in Linux kernel, published on 12 Jul 2024. 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: core: remove unnecessary WARN_ON() in implement()

Syzkaller hit a warning [1] in a call to implement() when trying
to write a value into a field of smaller size in an output report.

Since implement() already has a warn message printed out with the
help of hid_warn() and value in question gets trimmed with:
	...
	value &= m;
	...
WARN_ON may be considered superfluous. Remove it to suppress future
syzkaller triggers.

[1]
WARNING: CPU: 0 PID: 5084 at drivers/hid/hid-core.c:1451 implement drivers/hid/hid-core.c:1451 [inline]
WARNING: CPU: 0 PID: 5084 at drivers/hid/hid-core.c:1451 hid_output_report+0x548/0x760 drivers/hid/hid-core.c:1863
Modules linked in:
CPU: 0 PID: 5084 Comm: syz-executor424 Not tainted 6.9.0-rc7-syzkaller-00183-gcf87f46fd34d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
RIP: 0010:implement drivers/hid/hid-core.c:1451 [inline]
RIP: 0010:hid_output_report+0x548/0x760 drivers/hid/hid-core.c:1863
...
Call Trace:
 <TASK>
 __usbhid_submit_report drivers/hid/usbhid/hid-core.c:591 [inline]
 usbhid_submit_report+0x43d/0x9e0 drivers/hid/usbhid/hid-core.c:636
 hiddev_ioctl+0x138b/0x1f00 drivers/hid/usbhid/hiddev.c:726
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:904 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:890
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
...

Weakness: CWE-617 (Reachable Assertion)

## Which versions are affected by CVE-2024-39509?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-39509?

Apply the vendor's patch.

## Is CVE-2024-39509 being exploited?

There is no known exploitation of CVE-2024-39509 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-39509 and fix it if it is affected.

What it is: CVE-2024-39509 is a medium-severity denial of service vulnerability in Linux kernel, published on 12 Jul 2024. 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-2024-39509 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2024-39509/ (Markdown: https://insights.sbomify.com/CVE-2024-39509/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-39509
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-39509
- OSV: https://osv.dev/vulnerability/CVE-2024-39509

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-39509/
Summaries are generated and may contain mistakes; the official description above is the record.