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.
Advisories
Source ID Title
Debian DLA Debian DLA DLA-4904-1 linux-6.12 security update
Ubuntu USN Ubuntu USN USN-9019-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9020-1 Linux kernel vulnerabilities
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 21 Oct 2026 13:15:00 +0000


Wed, 30 Sep 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-663
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate


Fri, 25 Sep 2026 18:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-362
CWE-788

Fri, 25 Sep 2026 10:30:00 +0000

Type Values Removed Values Added
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.
Title perf/x86/intel: Prevent drain_pebs() reentry
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-10-21T12:53:50.943Z

Reserved: 2026-09-25T10:18:58.206Z

Link: CVE-2026-97960

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-25T11:17:23.720

Modified: 2026-10-21T13:21:17.560

Link: CVE-2026-97960

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-09-25T00:00:00Z

Links: CVE-2026-97960 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-01T04:45:12Z

Weaknesses