# CVE-2026-74709: xsk: clear metadata pointer when no timestamp is requested

> A local attacker can trigger a race condition in the Linux kernel XSK subsystem to write unauthorized timestamps into memory, potentially corrupting data.

- **Severity:** Not scored
- **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:** 22 Aug 2026
- **Also known as:** BELL-CVE-2026-74709, DEBIAN-CVE-2026-74709, GHSA-gg32-fqwc-p469, UBUNTU-CVE-2026-74709

## What is CVE-2026-74709?

CVE-2026-74709 is a memory corruption 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:

xsk: clear metadata pointer when no timestamp is requested

User space can change metadata flags after request processing. Rereading
them during completion can therefore make the kernel write a timestamp
that was not requested when the packet was submitted.

Clear the metadata pointer during request processing unless timestamp
completion is requested. Completion handling can then use the pointer
itself instead of rereading the flags.

On the mlx5 multi-packet WQE path metadata is evaluated per batch:
xsk_tx_metadata_request() runs only for the descriptor that starts a
session, just like the checksum offload that is applied once through the
shared WQE. Only that descriptor's pointer is reset, so completion
handling can record a timestamp for the other descriptors of the session
regardless of their own XDP_TXMD_FLAGS_TIMESTAMP bit. The write stays
inside the metadata area; the single-WQE, other zero-copy, and generic
paths reset the pointer per descriptor and are unaffected.

## Which versions are affected by CVE-2026-74709?


## How do I fix CVE-2026-74709?

Apply the vendor's patch.

## Is CVE-2026-74709 being exploited?

There is no known exploitation of CVE-2026-74709 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74709 and fix it if it is affected.

What it is: CVE-2026-74709 is a memory corruption 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-2026-74709 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-2026-74709/ (Markdown: https://insights.sbomify.com/CVE-2026-74709/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74709
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74709
- OSV: https://osv.dev/vulnerability/CVE-2026-74709

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74709/
Summaries are generated and may contain mistakes; the official description above is the record.