CVE-2026-90272

perf: arm_pmuv3: Zero initialize hw_id branch stack field

Published Sep 17, 2026 CVSS n/a EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

perf: arm_pmuv3: Zero initialize hw_id branch stack field

PERF_SAMPLE_BRANCH_HW_INDEX is supported by BRBE so hw_id is passed to
userspace, but it's never set by the BRBE driver. Zero initialize it as
it should be according to the docs:

* For the architectures whose raw branch records are
* already stored in age order, the hw_idx should be 0.

It's probably too risky to remove PERF_SAMPLE_BRANCH_HW_INDEX from BRBE
now in case anyone is setting it and reading the value, but zero
initializing the whole struct also protects against the same issue with
new fields that are added in the future.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-9019-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9020-1 Linux kernel vulnerabilities
History
Type Values Removed Values Added
Weaknesses CWE-200
CWE-788
Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: perf: arm_pmuv3: Zero initialize hw_id branch stack field PERF_SAMPLE_BRANCH_HW_INDEX is supported by BRBE so hw_id is passed to userspace, but it's never set by the BRBE driver. Zero initialize it as it should be according to the docs: * For the architectures whose raw branch records are * already stored in age order, the hw_idx should be 0. It's probably too risky to remove PERF_SAMPLE_BRANCH_HW_INDEX from BRBE now in case anyone is setting it and reading the value, but zero initializing the whole struct also protects against the same issue with new fields that are added in the future.
Title perf: arm_pmuv3: Zero initialize hw_id branch stack field
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Oct 19, 2026, 9:00 AM
Reserved
Sep 11, 2026, 7:38 PM
Status
Received
Published
Sep 17, 2026, 5:17 PM
Modified
Oct 19, 2026, 9:19 AM