CVE-2025-40216

Local kernel memory corruption via miscalculated folio offset

Published Dec 4, 2025 · Updated Aug 5, 2026

Memory corruption in Linux kernel 6.12 through 6.15.4 allows local users to read or write kernel memory via registered buffers. io_sqe_buffer_register masks the user virtual address by the folio size, so an unaligned pointer produces the wrong first-page offset after buffer coalescing. Unprivileged local access to io_uring fixed-buffer registration is sufficient; subsequent fixed I/O can disclose or alter memory or panic the kernel.

CVSS severity7.8
High
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in Linux kernel 6.12 through 6.15.4 allows local users to read or write kernel memory via registered buffers. io_sqe_buffer_register masks the user virtual address by the folio size, so an unaligned pointer produces the wrong first-page offset after buffer coalescing. Unprivileged local access to io_uring fixed-buffer registration is sufficient; subsequent fixed I/O can disclose or alter memory or panic the kernel.

The record

CVE
CVE-2025-40216
Published
Dec 4, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 4, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=6.12
  2. Affected versionversion=a8edbb424b1391b077407c75d8f5d2ede77aa70d <3a3c6d61577dbb23c09df3e21f6f9eda1ecd634b
  3. Affected versionversion=a8edbb424b1391b077407c75d8f5d2ede77aa70d <50998b0ae7d9d552e96d8b7239981cf05f65eff5
  4. Affected versionversion=a8edbb424b1391b077407c75d8f5d2ede77aa70d <f16769241594be59387b56ab525e327f54377e60

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.12; version=a8edbb424b1391b077407c75d8f5d2ede77aa70d <3a3c6d61577dbb23c09df3e21f6f9eda1ecd634b; version=a8edbb424b1391b077407c75d8f5d2ede77aa70d <50998b0ae7d9d552e96d8b7239981cf05f65eff5; version=a8edbb424b1391b077407c75d8f5d2ede77aa70d <f16769241594be59387b56ab525e327f54377e60

Published CVSS scores

7.8LinuxCVSS: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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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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