# CVE-2026-31467: erofs: add GFP_NOIO in the bio completion if needed

> A deadlock in the Linux kernel's EROFS filesystem can cause a denial of service when memory pressure triggers swapping during bio completion.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Apr 2026
- **Updated:** 5 Aug 2026
- **Also known as:** AZL-83363, BELL-CVE-2026-31467, DEBIAN-CVE-2026-31467, GHSA-v4fx-vwm3-3682, ROOT-OS-DEBIAN-11-CVE-2026-31467, ROOT-OS-DEBIAN-12-CVE-2026-31467, ROOT-OS-DEBIAN-13-CVE-2026-31467, ROOT-OS-UBUNTU-2204-CVE-2026-31467, ROOT-OS-UBUNTU-2404-CVE-2026-31467, UBUNTU-CVE-2026-31467

## What is CVE-2026-31467?

CVE-2026-31467 is a high-severity denial of service vulnerability in Linux kernel, published on 22 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

erofs: add GFP_NOIO in the bio completion if needed

The bio completion path in the process context (e.g. dm-verity)
will directly call into decompression rather than trigger another
workqueue context for minimal scheduling latencies, which can
then call vm_map_ram() with GFP_KERNEL.

Due to insufficient memory, vm_map_ram() may generate memory
swapping I/O, which can cause submit_bio_wait to deadlock
in some scenarios.

Trimmed down the call stack, as follows:

f2fs_submit_read_io
  submit_bio                      //bio_list is initialized.
    mmc_blk_mq_recovery
      z_erofs_endio
        vm_map_ram
          __pte_alloc_kernel
            __alloc_pages_direct_reclaim
              shrink_folio_list
                __swap_writepage
                  submit_bio_wait  //bio_list is non-NULL, hang!!!

Use memalloc_noio_{save,restore}() to wrap up this path.

Weakness: CWE-667 (Improper Locking)

## Which versions are affected by CVE-2026-31467?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31467?

Apply the vendor's patch.

## Is CVE-2026-31467 being exploited?

There is no known exploitation of CVE-2026-31467 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-2026-31467 and fix it if it is affected.

What it is: CVE-2026-31467 is a high-severity denial of service vulnerability in Linux kernel, published on 22 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-31467 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-2026-31467/ (Markdown: https://insights.sbomify.com/CVE-2026-31467/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31467
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31467
- OSV: https://osv.dev/vulnerability/CVE-2026-31467

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31467/
Summaries are generated and may contain mistakes; the official description above is the record.