# CVE-2026-99136: dm-crypt: fix a tiny race condition in crypt_dec_pending


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 28 Oct 2026
- **Updated:** 28 Oct 2026
- **Also known as:** AZL-111257, BELL-CVE-2026-99136, DEBIAN-CVE-2026-99136, GHSA-mgww-4g2j-r877, UBUNTU-CVE-2026-99136

## What is CVE-2026-99136?

CVE-2026-99136 is a vulnerability in Linux, published on 28 Oct 2026. 

### Official description

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

dm-crypt: fix a tiny race condition in crypt_dec_pending

crypt_dec_pending reads io->error before calling atomic_dec_and_test.
Another context, for example crypt_endio called from an interrupt, may
set io->error and drop its reference between the read and the
decrement. crypt_dec_pending then drops the last reference and completes
the bio with the stale status - so a read that failed and was never
decrypted, or a write that failed, is reported as successful.

The read was placed before the decrement by commit b35f8caa0890 ("dm
crypt: wait for endio to complete before destruction"), because that
commit freed dm_crypt_io before calling bio_endio. This is no longer the
case, dm_crypt_io lives in the per-bio data now.

Read io->error after atomic_dec_and_test instead. atomic_dec_and_test is
fully ordered, so no additional barrier is needed.

## Which versions are affected by CVE-2026-99136?


## How do I fix CVE-2026-99136?

Upgrade to a fixed version.

## Is CVE-2026-99136 being exploited?

There is no known exploitation of CVE-2026-99136 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-99136 and fix it if it is affected.

What it is: CVE-2026-99136 is a vulnerability in Linux, published on 28 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-99136 in the wild and no public exploit code.

Affected product: Linux. 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-2026-99136/ (Markdown: https://insights.sbomify.com/CVE-2026-99136/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-99136
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-99136
- OSV: https://osv.dev/vulnerability/CVE-2026-99136

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-99136/
Summaries are generated and may contain mistakes; the official description above is the record.