# CVE-2026-64251: pwrseq: core: fix use-after-free in pwrseq_debugfs_seq_next()

> A use-after-free in the Linux kernel pwrseq debugfs interface allows attackers to potentially execute code or escalate privileges.

- **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:** 24 Jul 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-64251, DEBIAN-CVE-2026-64251, GHSA-4mm9-h7gj-362g, ROOT-OS-UBUNTU-2204-CVE-2026-64251, UBUNTU-CVE-2026-64251

## What is CVE-2026-64251?

CVE-2026-64251 is a high-severity use after free vulnerability in Linux kernel, published on 24 Jul 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:

pwrseq: core: fix use-after-free in pwrseq_debugfs_seq_next()

pwrseq_debugfs_seq_next() declares 'next' with __free(put_device),
which causes put_device() to be called on the returned pointer when
the variable goes out of scope.  This results in a use-after-free
since the seq_file framework receives a pointer whose reference has
already been dropped.

Simply removing __free(put_device) would fix the UAF but would leak
the reference acquired by bus_find_next_device(), as stop() only
calls up_read(&pwrseq_sem) and never releases the device reference.

Fix this by making the reference counting consistent across all
seq_file callbacks, matching the standard pattern used by PCI and
SCSI:

- start(): use get_device() so it returns a referenced pointer.
- next(): explicitly put_device(curr) to release the previous
  device's reference (no NULL check needed - the seq_file framework
  only calls next() while the previous return was non-NULL).
- stop(): put_device(data) to release the last iterated device's
  reference, with a NULL guard since stop() may be called with NULL
  when start() returned NULL or next() reached end-of-sequence.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-64251?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-64251?

Apply the vendor's patch.

## Is CVE-2026-64251 being exploited?

There is no known exploitation of CVE-2026-64251 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-2026-64251 and fix it if it is affected.

What it is: CVE-2026-64251 is a high-severity use after free vulnerability in Linux kernel, published on 24 Jul 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-2026-64251 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-2026-64251/ (Markdown: https://insights.sbomify.com/CVE-2026-64251/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64251
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64251
- OSV: https://osv.dev/vulnerability/CVE-2026-64251

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64251/
Summaries are generated and may contain mistakes; the official description above is the record.