# CVE-2025-21810: driver core: class: Fix wild pointer dereferences in API class_dev_iter_next()

> A wild pointer dereference in the Linux kernel's class device iterator can cause a system crash, requiring a kernel patch to fix.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 27 Feb 2025
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2025-21810, DEBIAN-CVE-2025-21810, GHSA-p7wm-885p-3rmg, ROOT-OS-UBUNTU-2404-CVE-2025-21810, UBUNTU-CVE-2025-21810

## What is CVE-2025-21810?

CVE-2025-21810 is a high-severity vulnerability in Linux kernel, published on 27 Feb 2025. 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:

driver core: class: Fix wild pointer dereferences in API class_dev_iter_next()

There are a potential wild pointer dereferences issue regarding APIs
class_dev_iter_(init|next|exit)(), as explained by below typical usage:

// All members of @iter are wild pointers.
struct class_dev_iter iter;

// class_dev_iter_init(@iter, @class, ...) checks parameter @class for
// potential class_to_subsys() error, and it returns void type and does
// not initialize its output parameter @iter, so caller can not detect
// the error and continues to invoke class_dev_iter_next(@iter) even if
// @iter still contains wild pointers.
class_dev_iter_init(&iter, ...);

// Dereference these wild pointers in @iter here once suffer the error.
while (dev = class_dev_iter_next(&iter)) { ... };

// Also dereference these wild pointers here.
class_dev_iter_exit(&iter);

Actually, all callers of these APIs have such usage pattern in kernel tree.
Fix by:
- Initialize output parameter @iter by memset() in class_dev_iter_init()
  and give callers prompt by pr_crit() for the error.
- Check if @iter is valid in class_dev_iter_next().

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2025-21810?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-21810?

Apply the vendor's patch.

## Is CVE-2025-21810 being exploited?

There is no known exploitation of CVE-2025-21810 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-2025-21810 and fix it if it is affected.

What it is: CVE-2025-21810 is a high-severity vulnerability in Linux kernel, published on 27 Feb 2025. 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-2025-21810 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-2025-21810/ (Markdown: https://insights.sbomify.com/CVE-2025-21810/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-21810
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-21810
- OSV: https://osv.dev/vulnerability/CVE-2025-21810

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-21810/
Summaries are generated and may contain mistakes; the official description above is the record.