---
id: "CVE-2026-98854"
kind: "vulnerability"
aliases: ["CVE-2026-98854"]
title: "Linux kernel: device tree overlay error path can dereference NULL"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["arm", "embedded", "infrastructure", "linux-kernel"]
not_affected_if: ["no-device-tree-overlays"]
published_at: "2026-10-18T16:17:39+00:00"
first_seen_at: "2026-10-23T21:57:17+00:00"
updated_at: "2026-10-25T05:13:01+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98854", "first_seen_at": "2026-10-23T21:57:17+00:00"}]
---

# Linux kernel: device tree overlay error path can dereference NULL

When applying a device tree overlay fails during ID allocation, the kernel's cleanup path treats a negative ID as valid and calls list operations on an uninitialized list, which dereferences NULL. The sources describe a kernel crash from this bug; they do not state that an attacker can trigger it or gain control.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Run `uname -r` and compare against the fixed kernel version in your distribution's advisory (unknown from these sources)
- Check whether the device tree overlay subsystem is in use with `ls /sys/kernel/config/device-tree/overlays` (unknown if this path is used)

## Fix

- Update the Linux kernel to a release that includes the upstream commit 'of/overlay: only treat a positive changeset id as registered' (fixed version unknown from these sources)

## Timeline

- 2026-10-23T21:57:17+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98854

## From the sources

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

of/overlay: only treat a positive changeset id as registered

of_overlay_fdt_apply() stores the idr_alloc() return value in
ovcs->id before checking it. On failure the stored id is negative,
free_overlay_changeset()'s "if (ovcs->id)" check passes, idr_remove()
is called with a negative id and list_del() runs on ovcs->ovcs_list,
which is not initialized until after the id allocation. An allocation
failure at that point dereferences NULL.

Make free_overlay_changeset() treat only a strict-positive id as
registered. The rest of the function already copes with a
partially-initialized ovcs, so the error path stays a plain
goto err_free_ovcs.

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