CVE-2026-90272

Kernel-memory disclosure via uninitialized branch-stack hardware index

Published Sep 17, 2026 · Updated Sep 17, 2026

Information disclosure in Linux 6.17 arm_pmuv3 allows local users to read kernel memory via BRBE branch samples. The branch_records_alloc function allocates the branch stack without clearing it, and PERF_SAMPLE_BRANCH_HW_INDEX exposes its unset hw_idx field to userspace. Reachability requires BRBE-capable Arm hardware and permission to collect the relevant perf samples; the disclosed data is limited to the uninitialized field.

CVSS severity3.3
Low
EPSS probability0.21%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Linux 6.17 arm_pmuv3 allows local users to read kernel memory via BRBE branch samples. The branch_records_alloc function allocates the branch stack without clearing it, and PERF_SAMPLE_BRANCH_HW_INDEX exposes its unset hw_idx field to userspace. Reachability requires BRBE-capable Arm hardware and permission to collect the relevant perf samples; the disclosed data is limited to the uninitialized field.

The record

CVE
CVE-2026-90272
Published
Sep 17, 2026
Updated
Sep 17, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=58074a0fce66c6c97b35ce8a28ed4e7b780f9a8f <57b72442c1672963fd51ab441ca1b71f6dc79b66
  2. Affected versionversion=58074a0fce66c6c97b35ce8a28ed4e7b780f9a8f <7c3b63386c27bed8d59a4b4c283d02860420eb0a
  3. Affected versionversion=58074a0fce66c6c97b35ce8a28ed4e7b780f9a8f <988e11b69ef9d4034e19c64407030fa948580c3d
  4. Affected versionversion=6.17

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=58074a0fce66c6c97b35ce8a28ed4e7b780f9a8f <57b72442c1672963fd51ab441ca1b71f6dc79b66; version=58074a0fce66c6c97b35ce8a28ed4e7b780f9a8f <7c3b63386c27bed8d59a4b4c283d02860420eb0a; version=58074a0fce66c6c97b35ce8a28ed4e7b780f9a8f <988e11b69ef9d4034e19c64407030fa948580c3d; version=6.17

Published CVSS scores

3.3Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
5.1TenableCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:U/RC:C
2.1TenableAV:L/AC:L/Au:N/C:P/I:N/A:N
5.5TenableCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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