# CVE-2026-43188: ceph: do not propagate page array emplacement errors as batch errors

> A logic error in the Ceph filesystem code can cause a kernel oops when fscrypt is enabled, leading to a denial of service.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 6 May 2026
- **Updated:** 21 Oct 2026
- **Also known as:** BELL-CVE-2026-43188, DEBIAN-CVE-2026-43188, GHSA-qpxp-qjrm-7f7r, UBUNTU-CVE-2026-43188

## What is CVE-2026-43188?

CVE-2026-43188 is a medium-severity vulnerability in Linux kernel, published on 6 May 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:

ceph: do not propagate page array emplacement errors as batch errors

When fscrypt is enabled, move_dirty_folio_in_page_array() may fail
because it needs to allocate bounce buffers to store the encrypted
versions of each folio. Each folio beyond the first allocates its bounce
buffer with GFP_NOWAIT. Failures are common (and expected) under this
allocation mode; they should flush (not abort) the batch.

However, ceph_process_folio_batch() uses the same `rc` variable for its
own return code and for capturing the return codes of its routine calls;
failing to reset `rc` back to 0 results in the error being propagated
out to the main writeback loop, which cannot actually tolerate any
errors here: once `ceph_wbc.pages` is allocated, it must be passed to
ceph_submit_write() to be freed. If it survives until the next iteration
(e.g. due to the goto being followed), ceph_allocate_page_array()'s
BUG_ON() will oops the worker.

Note that this failure mode is currently masked due to another bug
(addressed next in this series) that prevents multiple encrypted folios
from being selected for the same write.

For now, just reset `rc` when redirtying the folio to prevent errors in
move_dirty_folio_in_page_array() from propagating. Note that
move_dirty_folio_in_page_array() is careful never to return errors on
the first folio, so there is no need to check for that. After this
change, ceph_process_folio_batch() no longer returns errors; its only
remaining failure indicator is `locked_pages == 0`, which the caller
already handles correctly.

## Which versions are affected by CVE-2026-43188?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43188?

Apply the vendor's patch.

## Is CVE-2026-43188 being exploited?

There is no known exploitation of CVE-2026-43188 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-2026-43188 and fix it if it is affected.

What it is: CVE-2026-43188 is a medium-severity vulnerability in Linux kernel, published on 6 May 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-2026-43188 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-2026-43188/ (Markdown: https://insights.sbomify.com/CVE-2026-43188/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43188
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43188
- OSV: https://osv.dev/vulnerability/CVE-2026-43188

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43188/
Summaries are generated and may contain mistakes; the official description above is the record.