# CVE-2026-97960: perf/x86/intel: Prevent drain_pebs() reentry

> A race condition in the Linux kernel's Intel PEBS handling allows local attackers to trigger out-of-bounds memory access, potentially leading to privilege escalation or code execution.

- **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-104360, BELL-CVE-2026-97960, DEBIAN-CVE-2026-97960, GHSA-5xpp-w3qp-6w34, UBUNTU-CVE-2026-97960

## What is CVE-2026-97960?

CVE-2026-97960 is a 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/x86/intel: Prevent drain_pebs() reentry

The PEBS buffer is shared by all events on a CPU, so drain_pebs() must
not be reentered. If so, one instance may observe stale buffer state and
potentially access out-of-bound memory.

Most invocations happen in NMI context, which naturally prevents reentry.
However, drain_pebs() is also reachable from process context via
intel_pmu_drain_pebs_buffer().

In those paths, the PMU is often already disabled, but not guaranteed.
For example, __intel_pmu_pebs_disable() only disables the target counter,
so other active counters can still raise a PMI and interrupt an in-flight
drain_pebs(). Here is an example,

__perf_addr_filters_adjust()
  perf_event_stop()
    __perf_event_stop()
      x86_pmu_stop() (event->pmu->stop)
        intel_pmu_disable_event()
          intel_pmu_pebs_disable()
            __intel_pmu_pebs_disable()
              intel_pmu_drain_large_pebs()
                intel_pmu_drain_pebs_buffer()

Introduce __intel_pmu_quiesce() and __intel_pmu_resume() helpers and
use them in intel_pmu_drain_large_pebs() to disable the full PMU
around the intel_pmu_drain_pebs_buffer() call, preventing reentry.

Also add a warning in intel_pmu_drain_pebs_buffer() when the full PMU is
not disabled.

## Which versions are affected by CVE-2026-97960?


## How do I fix CVE-2026-97960?

Apply the vendor's patch.

## Is CVE-2026-97960 being exploited?

There is no known exploitation of CVE-2026-97960 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-97960 and fix it if it is affected.

What it is: CVE-2026-97960 is a 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-2026-97960 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-2026-97960/ (Markdown: https://insights.sbomify.com/CVE-2026-97960/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97960
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97960
- OSV: https://osv.dev/vulnerability/CVE-2026-97960

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-97960/
Summaries are generated and may contain mistakes; the official description above is the record.