# CVE-2026-46274: io-wq: check that the predecessor is hashed in io_wq_remove_pending()

> A use-after-free vulnerability in the Linux kernel's io-wq subsystem allows attackers to execute arbitrary code or escalate privileges via dangling pointers.

- **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:** 8 Jun 2026
- **Updated:** 5 Aug 2026
- **Also known as:** AZL-89609, BELL-CVE-2026-46274, DEBIAN-CVE-2026-46274, GHSA-52w9-98q8-6pwf, ROOT-OS-DEBIAN-11-CVE-2026-46274, ROOT-OS-DEBIAN-12-CVE-2026-46274, ROOT-OS-DEBIAN-13-CVE-2026-46274, ROOT-OS-UBUNTU-2204-CVE-2026-46274, ROOT-OS-UBUNTU-2404-CVE-2026-46274, UBUNTU-CVE-2026-46274

## What is CVE-2026-46274?

CVE-2026-46274 is a high-severity use after free vulnerability in Linux kernel, published on 8 Jun 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:

io-wq: check that the predecessor is hashed in io_wq_remove_pending()

io_wq_remove_pending() needs to fix up wq->hash_tail[] if the cancelled
work was the tail of its hash bucket. When doing this, it checks whether
the preceding entry in acct->work_list has the same hash value, but
never checks that the predecessor is hashed at all. io_get_work_hash()
is simply atomic_read(&work->flags) >> IO_WQ_HASH_SHIFT, and the hash
bits are never set for non-hashed work, so it returns 0. Thus, when a
hashed bucket-0 work is cancelled while a non-hashed work is its list
predecessor, the check spuriously passes and a pointer to the non-hashed
io_kiocb is stored in wq->hash_tail[0].

Because non-hashed work is dequeued via the fast path in
io_get_next_work(), which never touches hash_tail[], the stale pointer
is never cleared. Therefore, after the non-hashed io_kiocb completes and
is freed back to req_cachep, wq->hash_tail[0] is a dangling pointer. The
io_wq is per-task (tctx->io_wq) and survives ring open/close, so the
dangling pointer persists for the lifetime of the task; the next hashed
bucket-0 enqueue dereferences it in io_wq_insert_work() and
wq_list_add_after() writes through freed memory.

Add the missing io_wq_is_hashed() check so a non-hashed predecessor
never inherits a hash_tail[] slot.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-46274?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-46274?

Apply the vendor's patch.

## Is CVE-2026-46274 being exploited?

There is no known exploitation of CVE-2026-46274 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-2026-46274 and fix it if it is affected.

What it is: CVE-2026-46274 is a high-severity use after free vulnerability in Linux kernel, published on 8 Jun 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-2026-46274 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-2026-46274/ (Markdown: https://insights.sbomify.com/CVE-2026-46274/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-46274
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46274
- OSV: https://osv.dev/vulnerability/CVE-2026-46274

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-46274/
Summaries are generated and may contain mistakes; the official description above is the record.