# CVE-2026-74471: tracing: Check return value of __register_event() in trace_module_add_events()

> A use-after-free vulnerability in the Linux kernel tracing subsystem allows attackers to execute arbitrary code or escalate privileges via module loading failures.

- **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:** 15 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** AZL-96021, BELL-CVE-2026-74471, DEBIAN-CVE-2026-74471, GHSA-437h-q69x-6qrx, UBUNTU-CVE-2026-74471

## What is CVE-2026-74471?

CVE-2026-74471 is a high-severity use after free vulnerability in Linux, published on 15 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:

tracing: Check return value of __register_event() in trace_module_add_events()

trace_module_add_events() ignores the return value of __register_event()
and unconditionally calls __add_event_to_tracers() for each event.

If __register_event() fails (for example, if event_init() fails), the
trace_event_call is not added to ftrace_events list, but
__add_event_to_tracers() still creates a trace_event_file pointing to it.
If module loading subsequently fails and module memory is freed, tracing
state retains a stale trace_event_call pointer in trace_event_file,
leading to a use-after-free when tracefs or tracing subsystem operations
are later executed.

Fix this by checking the return value of __register_event() and only
calling __add_event_to_tracers() if event registration succeeded.

## Which versions are affected by CVE-2026-74471?


## How do I fix CVE-2026-74471?

Apply the vendor's patch.

## Is CVE-2026-74471 being exploited?

There is no known exploitation of CVE-2026-74471 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74471 and fix it if it is affected.

What it is: CVE-2026-74471 is a high-severity use after free vulnerability in Linux, published on 15 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-2026-74471 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-2026-74471/ (Markdown: https://insights.sbomify.com/CVE-2026-74471/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74471
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74471
- OSV: https://osv.dev/vulnerability/CVE-2026-74471

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74471/
Summaries are generated and may contain mistakes; the official description above is the record.