# CVE-2026-74647: misc: fastrpc: Remove buffer from list prior to unmap operation

> A race condition in the Linux kernel fastrpc driver allows concurrent unmap operations to corrupt buffer state, potentially leading to undefined behavior.

- **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:** 22 Aug 2026
- **Updated:** 27 Aug 2026
- **Also known as:** BELL-CVE-2026-74647, DEBIAN-CVE-2026-74647, GHSA-4jph-32qw-h3gw, UBUNTU-CVE-2026-74647

## What is CVE-2026-74647?

CVE-2026-74647 is a high-severity vulnerability in Linux, published on 22 Aug 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:

misc: fastrpc: Remove buffer from list prior to unmap operation

fastrpc_req_munmap_impl() is called to unmap any buffer. The buffer is
getting removed from the list after it is unmapped from DSP. This can
create potential race conditions if multiple threads invoke unmap
concurrently, where one thread may remove the entry from the list while
another thread's unmap operation is still ongoing.

Fix this by removing the buffer entry from the list before calling the
unmap operation. If the unmap fails, the entry is re-added to the list
so that userspace can retry the unmap, or alternatively, the buffer
will be cleaned up during device release when the DSP process is torn
down and all DSP-side mappings are freed along with remaining buffers
in the list.

## Which versions are affected by CVE-2026-74647?


## How do I fix CVE-2026-74647?

Apply the vendor's patch.

## Is CVE-2026-74647 being exploited?

There is no known exploitation of CVE-2026-74647 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74647 and fix it if it is affected.

What it is: CVE-2026-74647 is a high-severity vulnerability in Linux, published on 22 Aug 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-2026-74647 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-2026-74647/ (Markdown: https://insights.sbomify.com/CVE-2026-74647/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74647
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74647
- OSV: https://osv.dev/vulnerability/CVE-2026-74647

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74647/
Summaries are generated and may contain mistakes; the official description above is the record.