# CVE-2026-68283: tracing: Fix use-after-free freeing trigger private data

> A use-after-free in Linux kernel tracing allows attackers to execute arbitrary code or escalate privileges via race conditions in trigger data handling.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/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:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-68283, GHSA-p3cm-8j25-92w5, UBUNTU-CVE-2026-68283

## What is CVE-2026-68283?

CVE-2026-68283 is a high-severity use after free vulnerability in Linux, published on 10 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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

tracing: Fix use-after-free freeing trigger private data

Commit 61d445af0a7c ("tracing: Add bulk garbage collection of freeing
event_trigger_data") moved the kfree() of event_trigger_data to a kthread
that runs tracepoint_synchronize_unregister() before freeing. That removed
the synchronization the trigger .free callbacks used to get implicitly and
inline from trigger_data_free().

event_hist_trigger_free(), event_hist_trigger_named_free() and
event_enable_trigger_free() free their satellite data (hist_data, cmd_ops,
enable_data) right after trigger_data_free() returns. With the
synchronization now deferred to the kthread, a concurrent tracepoint
handler can still reach that data through the list_del_rcu()'d trigger,
causing a use-after-free.

The histogram teardown must stay synchronous: remove_hist_vars() and
unregister_field_var_hists() have to detach a synthetic event from the
histogram before the trigger-removal write returns, otherwise a following
command races in and the synthetic-event removal fails with -EBUSY, as the
trigger-synthetic-eprobe.tc selftest catches. Make those callbacks wait
with the correct barrier - tracepoint_synchronize_unregister(), matching
the free kthread - before freeing.

The enable trigger has no such synchronous requirement, and a blocking
synchronize there would re-serialize the path that commit deliberately
deferred. Give it an optional private_data_free() callback that the free
kthread runs after its grace period, and free enable_data from there.

## Which versions are affected by CVE-2026-68283?


## How do I fix CVE-2026-68283?

Apply the vendor's patch.

## Is CVE-2026-68283 being exploited?

There is no known exploitation of CVE-2026-68283 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68283 and fix it if it is affected.

What it is: CVE-2026-68283 is a high-severity use after free vulnerability in Linux, published on 10 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-68283 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-2026-68283/ (Markdown: https://insights.sbomify.com/CVE-2026-68283/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68283
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68283
- OSV: https://osv.dev/vulnerability/CVE-2026-68283

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68283/
Summaries are generated and may contain mistakes; the official description above is the record.