CVE-2026-64402

Local kernel memory corruption via unnormalized AUX head

Published Jul 25, 2026 · Updated Jul 25, 2026

Out-of-bounds write in the Linux Kernel allows local users to corrupt kernel memory through an UltraSoC SMB perf AUX sink. smb_sync_perf_buffer() derives pg_idx from an unnormalized handle->head and indexes dst_pages[] before reducing the index modulo nr_pages. The path requires local low-privileged access and an UltraSoC SMB device configured as a perf AUX sink; the write compromises kernel confidentiality, integrity, and availability.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in the Linux Kernel allows local users to corrupt kernel memory through an UltraSoC SMB perf AUX sink. smb_sync_perf_buffer() derives pg_idx from an unnormalized handle->head and indexes dst_pages[] before reducing the index modulo nr_pages. The path requires local low-privileged access and an UltraSoC SMB device configured as a perf AUX sink; the write compromises kernel confidentiality, integrity, and availability.

The record

CVE
CVE-2026-64402
Published
Jul 25, 2026
Updated
Jul 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 25, 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=06f5c2926aaa0fba7f99678da6ef77cbbbda1441 <38dbc8db8341ccdf8e1e1a067453d33ad751864b
  2. Affected versionversion=06f5c2926aaa0fba7f99678da6ef77cbbbda1441 <4c5a0a946373da99a80398289b28845b5ae40cd1
  3. Affected versionversion=06f5c2926aaa0fba7f99678da6ef77cbbbda1441 <661a019ac0413ecec9e5d1dfcc12fbca8e78d5fb
  4. Affected versionversion=06f5c2926aaa0fba7f99678da6ef77cbbbda1441 <98495b5a4d77dd22e106f462b76e1093a55b29a7
  5. Affected versionversion=06f5c2926aaa0fba7f99678da6ef77cbbbda1441 <daf6246ab988fc8bdc82ad7c8d0b1c182d11b15f
  6. Affected versionversion=6.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=06f5c2926aaa0fba7f99678da6ef77cbbbda1441 <38dbc8db8341ccdf8e1e1a067453d33ad751864b; version=06f5c2926aaa0fba7f99678da6ef77cbbbda1441 <4c5a0a946373da99a80398289b28845b5ae40cd1; version=06f5c2926aaa0fba7f99678da6ef77cbbbda1441 <661a019ac0413ecec9e5d1dfcc12fbca8e78d5fb; version=06f5c2926aaa0fba7f99678da6ef77cbbbda1441 <98495b5a4d77dd22e106f462b76e1093a55b29a7; version=06f5c2926aaa0fba7f99678da6ef77cbbbda1441 <daf6246ab988fc8bdc82ad7c8d0b1c182d11b15f; version=6.3

Published CVSS scores

7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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.

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

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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