# CVE-2026-74429: rxrpc: Fix the reception of a reply packet before data transmission

> A null pointer dereference in the Linux kernel's rxrpc module can cause a system crash when a reply packet is received before data transmission.

- **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:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-74429, DEBIAN-CVE-2026-74429, GHSA-p3f2-6553-5mwv, UBUNTU-CVE-2026-74429

## What is CVE-2026-74429?

CVE-2026-74429 is a high-severity vulnerability in Linux, published on 15 Aug 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:

rxrpc: Fix the reception of a reply packet before data transmission

Fix rxrpc_receiving_reply() to handle the reception of an apparent reply
DATA packet before rxrpc has had a chance to send any request DATA packets
on a client call by checking to see if the call has been exposed yet by
sending the first packet.

Without this, rxrpc_rotate_tx_window() might oops.

Also fix rxrpc_rotate_tx_window() to handle the Tx queue being empty by
changing the do...while loop into a while loop, just in case a call is
abnormally terminated by an early reply before the last request packet is
transmitted.

## Which versions are affected by CVE-2026-74429?


## How do I fix CVE-2026-74429?

Apply the vendor's patch.

## Is CVE-2026-74429 being exploited?

There is no known exploitation of CVE-2026-74429 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74429 and fix it if it is affected.

What it is: CVE-2026-74429 is a high-severity vulnerability in Linux, published on 15 Aug 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-2026-74429 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-2026-74429/ (Markdown: https://insights.sbomify.com/CVE-2026-74429/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74429
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74429
- OSV: https://osv.dev/vulnerability/CVE-2026-74429

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74429/
Summaries are generated and may contain mistakes; the official description above is the record.