# CVE-2026-97961: perf/core: Allow list_del during perf_event_overflow()

> A local attacker can trigger list corruption in the Linux kernel perf subsystem, potentially causing a denial of service or privilege escalation.

- **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:** 25 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-104247, BELL-CVE-2026-97961, DEBIAN-CVE-2026-97961, GHSA-prpp-c3xm-jcfh, UBUNTU-CVE-2026-97961

## What is CVE-2026-97961?

CVE-2026-97961 is an use after free vulnerability in Linux, published on 25 Sep 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:

perf/core: Allow list_del during perf_event_overflow()

A PMU might use perf_sched_cb_inc() and perf_sched_cb_dec()
interface to get the PMU call back function pmu::sched_task
invoked at schedule in and schedule out. This is achieved
by walking along the list anchored by sched_cb_list.

The following scenario might lead to a list corruption.

   perf_pmu_sched_task()
      for_each_list_entry(..., &sched_cb_list)
      +--> __perf_pmu_sched_task()
           +--> event->pmu->sched_task())
                +--> PMU_push_sample()
                     +--> perf_event_overflow()
                          +--> __perf_event_overflow()
                               +--> pmu->stop()
                                    +--> perf_sched_cb_dec()
                                         remove entry from sched_cb_list
                                         while list node in use.

This happens when ioctl(fd, PERF_EVENT_IOC_REFRESH, xxx) has been
invoked and perf_event::event_limit hits zero.

Prevent the list corruption and convert for_each_list_entry()
to for_each_list_entry_safe().

## Which versions are affected by CVE-2026-97961?


## How do I fix CVE-2026-97961?

Apply the vendor's patch.

## Is CVE-2026-97961 being exploited?

There is no known exploitation of CVE-2026-97961 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-97961 and fix it if it is affected.

What it is: CVE-2026-97961 is an use after free vulnerability in Linux, published on 25 Sep 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-2026-97961 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-2026-97961/ (Markdown: https://insights.sbomify.com/CVE-2026-97961/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97961
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97961
- OSV: https://osv.dev/vulnerability/CVE-2026-97961

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-97961/
Summaries are generated and may contain mistakes; the official description above is the record.