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Full vulnerability report · 2026
CVE-2026-43073High confidence

x86-64: rename misleadingly named '__copy_user_nocache()' function

Linux · Linux

5.5MediumCVSS 3.1
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
Distribution package intelligence

Ubuntu vendor package status

Canonical’s release and source-package findings are shown separately from local repository availability.

20 package states
Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Ubuntu releaseSource packageVendor stateFixed versionEvidence
Ubuntu 24.04 LTSnoble · standard archivelinuxAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-awsAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-azureAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-azure-fdeAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-azure-nvidiaAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-gcpAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-gkeAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-gkeopAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-ibmAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-lowlatencyAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-nvidiaAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-nvidia-lowlatencyAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-nvidia-tegraAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-oem-6.11Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-oracleAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-raspiAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-raspi-realtimeAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-realtimeAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-riscvAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-xilinxAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-27378

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
01

What, why and how

In the Linux kernel, the following vulnerability has been resolved: x86-64: rename misleadingly named '__copy_user_nocache()' function This function was a masterclass in bad naming, for various historical reasons. It claimed to be a non-cached user copy. It is literally _neither_ of those things. It's a specialty memory copy routine that uses non-temporal stores for the destination (but not the source), and that does exception handling for both source and destination accesses. Also note that while it works for unaligned targets, any unaligned parts (whether at beginning or end) will not use non-temporal stores, since only words and quadwords can be non-temporal on x86. The exception handling means that it _can_ be used for user space accesses, but not on its own - it needs all the normal "start user space access" logic around it. But typically the user space access would be the source, not the non-temporal destination. That was the original intention of this, where the destination was some fragile persistent memory target that needed non-temporal stores in order to catch machine check exceptions synchronously and deal with them gracefully. Thus that non-descriptive name: one use case was to copy from user space into a non-cached kernel buffer. However, the existing users are a mix of that intended use-case, and a couple of random drivers that just did this as a performance tweak. Some of those random drivers then actively misused the user copying version (with STAC/CLAC and all) to do kernel copies without ever even caring about the exception handling, _just_ for the non-temporal destination. Rename it as a first small step to actually make it halfway sane, and change the prototype to be more normal: it doesn't take a user pointer unless the caller has done the proper conversion, and the argument size is the full size_t (it still won't actually copy more than 4GB in one go, but there's also no reason to silently truncate the size argument in the caller). Finally, use this now sanely named function in the NTB code, which mis-used a user copy version (with STAC/CLAC and all) of this interface despite it not actually being a user copy at all.

What

In the Linux kernel, the following vulnerability has been resolved: x86-64: rename misleadingly named '__copy_user_nocache()' function This function was a masterclass in bad naming, for various historical reasons. It claimed to be a non-cached user copy. It is literally _neither_ of those things. It's a specialty memory copy routine that uses non-temporal stores for the destination (but not the source), and that does exception handling for both source and destination accesses. Also note that while it works for unaligned targets, any unaligned parts (whether at beginning or end) will not use non-temporal stores, since only words and quadwords can be non-temporal on x86. The exception handling means that it _can_ be used for user space accesses, but not on its own - it needs all the normal "start user space access" logic around it. But typically the user space access would be the source, not the non-temporal destination. That was the original intention of this, where the destination was some fragile persistent memory target that needed non-temporal stores in order to catch machine check exceptions synchronously and deal with them gracefully. Thus that non-descriptive name: one use case was to copy from user space into a non-cached kernel buffer. However, the existing users are a mix of that intended use-case, and a couple of random drivers that just did this as a performance tweak. Some of those random drivers then actively misused the user copying version (with STAC/CLAC and all) to do kernel copies without ever even caring about the exception handling, _just_ for the non-temporal destination. Rename it as a first small step to actually make it halfway sane, and change the prototype to be more normal: it doesn't take a user pointer unless the caller has done the proper conversion, and the argument size is the full size_t (it still won't actually copy more than 4GB in one go, but there's also no reason to silently truncate the size argument in the caller). Finally, use this now sanely named function in the NTB code, which mis-used a user copy version (with STAC/CLAC and all) of this interface despite it not actually being a user copy at all.

Why

The current structured CVE record identifies a security weakness, but the root cause requires confirmation in the linked vendor material.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

In the Linux kernel, the following vulnerability has been resolved: x86-64: rename misleadingly named '__copy_user_nocache()' function This function was a masterclass in bad naming, for various historical reasons. It claimed to be a non-cached user copy. It is literally _neither_ of those things. It's a specialty memory copy routine that uses non-temporal stores for the destination (but not the source), and that does exception handling for both source and destination accesses. Also note that while it works for unaligned targets, any unaligned parts (whether at beginning or end) will not use non-temporal stores, since only words and quadwords can be non-temporal on x86. The exception handling means that it _can_ be used for user space accesses, but not on its own - it needs all the normal "start user space access" logic around it. But typically the user space access would be the source, not the non-temporal destination. That was the original intention of this, where the destination was some fragile persistent memory target that needed non-temporal stores in order to catch machine check exceptions synchronously and deal with them gracefully. Thus that non-descriptive name: one use case was to copy from user space into a non-cached kernel buffer. However, the existing users are a mix of that intended use-case, and a couple of random drivers that just did this as a performance tweak. Some of those random drivers then actively misused the user copying version (with STAC/CLAC and all) to do kernel copies without ever even caring about the exception handling, _just_ for the non-temporal destination. Rename it as a first small step to actually make it halfway sane, and change the prototype to be more normal: it doesn't take a user pointer unless the caller has done the proper conversion, and the argument size is the full size_t (it still won't actually copy more than 4GB in one go, but there's also no reason to silently truncate the size argument in the caller). Finally, use this now sanely named function in the NTB code, which mis-used a user copy version (with STAC/CLAC and all) of this interface despite it not actually being a user copy at all.

Why

The current structured CVE record identifies a security weakness, but the root cause requires confirmation in the linked vendor material.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
local access → vulnerable operation → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Local
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration.
CWE not yet assigned
CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-2026-1385Linux Kernel: Mehrere Schwachstellen

Ein lokaler Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um einen Denial of Service zu verursachen, Informationen offenzulegen, Sicherheitsmaßnahmen zu umgehen oder potentiell beliebigen Programmcode auszuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260506Security Bulletin 06 May 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 06 May 2026, published on 6 May 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-1066Multiples vulnérabilités dans le noyau Linux d'Ubuntu

d?id=CVE-2026-43061 Référence CVE CVE-2026-43062 https://www.cve.org/CVERecord?id=CVE-2026-43062 Référence CVE CVE-2026-43064 https://www.cve.org/CVERecord?id=CVE-2026-43064 Référence CVE CVE-2026-43065 https://www.cve.org/CVERecord?id=CVE-2026-43065 Référence CVE CVE-2026-43066 https://www.cve.org/CVERecord?id=CVE-2026-43066 Référence CVE CVE-2026-43068 https://www.cve.org/CVERecord?id=CVE-2026-43068 Référence CVE CVE-2026-43069 https://www.cve.org/CVERecord?id=CVE-2026-43069 Référence CVE CVE-2026-43071 https://www.cve.org/CVERecord?id=CVE-2026-43071 Référence CVE CVE-2026-43072 https://www.cve.org/CVERecord?id=CVE-2026-43072 Référence CVE CVE-2026-43073 https://www.cve.org/CVERecord?id=CVE-2026-43073 Référence CVE CVE-2026-43074 https://www.cve.org/CVERecord?id=CVE-2026-43074 Référence CVE CVE-2026-43075 https://www.cve.org/CVERecord?id=CVE-2026-43075 Référence CVE CVE-2026-43076 https://www.cve.org/CVERecord?id=CVE-2026-43076 Référence CVE CVE-2026-43079 https://www.cve.org/CVERecord?id=CVE-2026-43079 Référence CVE CVE-2026-43080 https://www.cve.org/CVERecord?id=CVE-2026-43080 Référence CVE CVE-2026-43081 https://www.cve.org/CVERecord?id=CVE-2026-43081 Référence CVE CVE-2026-43082 https://www.cve.org/CVERecord?id=CVE-2026-43082 Référence CVE CVE-2026-43083 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0954Multiples vulnérabilités dans le noyau Linux d'Ubuntu

d?id=CVE-2026-43061 Référence CVE CVE-2026-43062 https://www.cve.org/CVERecord?id=CVE-2026-43062 Référence CVE CVE-2026-43064 https://www.cve.org/CVERecord?id=CVE-2026-43064 Référence CVE CVE-2026-43065 https://www.cve.org/CVERecord?id=CVE-2026-43065 Référence CVE CVE-2026-43066 https://www.cve.org/CVERecord?id=CVE-2026-43066 Référence CVE CVE-2026-43068 https://www.cve.org/CVERecord?id=CVE-2026-43068 Référence CVE CVE-2026-43069 https://www.cve.org/CVERecord?id=CVE-2026-43069 Référence CVE CVE-2026-43071 https://www.cve.org/CVERecord?id=CVE-2026-43071 Référence CVE CVE-2026-43072 https://www.cve.org/CVERecord?id=CVE-2026-43072 Référence CVE CVE-2026-43073 https://www.cve.org/CVERecord?id=CVE-2026-43073 Référence CVE CVE-2026-43074 https://www.cve.org/CVERecord?id=CVE-2026-43074 Référence CVE CVE-2026-43075 https://www.cve.org/CVERecord?id=CVE-2026-43075 Référence CVE CVE-2026-43076 https://www.cve.org/CVERecord?id=CVE-2026-43076 Référence CVE CVE-2026-43079 https://www.cve.org/CVERecord?id=CVE-2026-43079 Référence CVE CVE-2026-43080 https://www.cve.org/CVERecord?id=CVE-2026-43080 Référence CVE CVE-2026-43081 https://www.cve.org/CVERecord?id=CVE-2026-43081 Référence CVE CVE-2026-43082 https://www.cve.org/CVERecord?id=CVE-2026-43082 Référence CVE CVE-2026-43083 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0926Multiples vulnérabilités dans le noyau Linux d'Ubuntu

d?id=CVE-2026-43061 Référence CVE CVE-2026-43062 https://www.cve.org/CVERecord?id=CVE-2026-43062 Référence CVE CVE-2026-43064 https://www.cve.org/CVERecord?id=CVE-2026-43064 Référence CVE CVE-2026-43065 https://www.cve.org/CVERecord?id=CVE-2026-43065 Référence CVE CVE-2026-43066 https://www.cve.org/CVERecord?id=CVE-2026-43066 Référence CVE CVE-2026-43068 https://www.cve.org/CVERecord?id=CVE-2026-43068 Référence CVE CVE-2026-43069 https://www.cve.org/CVERecord?id=CVE-2026-43069 Référence CVE CVE-2026-43071 https://www.cve.org/CVERecord?id=CVE-2026-43071 Référence CVE CVE-2026-43072 https://www.cve.org/CVERecord?id=CVE-2026-43072 Référence CVE CVE-2026-43073 https://www.cve.org/CVERecord?id=CVE-2026-43073 Référence CVE CVE-2026-43074 https://www.cve.org/CVERecord?id=CVE-2026-43074 Référence CVE CVE-2026-43075 https://www.cve.org/CVERecord?id=CVE-2026-43075 Référence CVE CVE-2026-43076 https://www.cve.org/CVERecord?id=CVE-2026-43076 Référence CVE CVE-2026-43079 https://www.cve.org/CVERecord?id=CVE-2026-43079 Référence CVE CVE-2026-43080 https://www.cve.org/CVERecord?id=CVE-2026-43080 Référence CVE CVE-2026-43081 https://www.cve.org/CVERecord?id=CVE-2026-43081 Référence CVE CVE-2026-43082 https://www.cve.org/CVERecord?id=CVE-2026-43082 Référence CVE CVE-2026-43083 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0861Multiples vulnérabilités dans le noyau Linux d'Ubuntu

d?id=CVE-2026-31718 Référence CVE CVE-2026-31719 https://www.cve.org/CVERecord?id=CVE-2026-31719 Référence CVE CVE-2026-43011 https://www.cve.org/CVERecord?id=CVE-2026-43011 Référence CVE CVE-2026-43033 https://www.cve.org/CVERecord?id=CVE-2026-43033 Référence CVE CVE-2026-43037 https://www.cve.org/CVERecord?id=CVE-2026-43037 Référence CVE CVE-2026-43038 https://www.cve.org/CVERecord?id=CVE-2026-43038 Référence CVE CVE-2026-43058 https://www.cve.org/CVERecord?id=CVE-2026-43058 Référence CVE CVE-2026-43071 https://www.cve.org/CVERecord?id=CVE-2026-43071 Référence CVE CVE-2026-43072 https://www.cve.org/CVERecord?id=CVE-2026-43072 Référence CVE CVE-2026-43073 https://www.cve.org/CVERecord?id=CVE-2026-43073 Référence CVE CVE-2026-43077 https://www.cve.org/CVERecord?id=CVE-2026-43077 Référence CVE CVE-2026-43078 https://www.cve.org/CVERecord?id=CVE-2026-43078 Référence CVE CVE-2026-43083 https://www.cve.org/CVERecord?id=CVE-2026-43083 Référence CVE CVE-2026-43114 https://www.cve.org/CVERecord?id=CVE-2026-43114 Référence CVE CVE-2026-43117 https://www.cve.org/CVERecord?id=CVE-2026-43117 Référence CVE CVE-2026-43123 https://www.cve.org/CVERecord?id=CVE-2026-43123 Référence CVE CVE-2026-43124 https://www.cve.org/CVERecord?id=CVE-2026-43124 Référence CVE CVE-2026-43125 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0831Multiples vulnérabilités dans le noyau Linux d'Ubuntu

d?id=CVE-2026-31718 Référence CVE CVE-2026-31719 https://www.cve.org/CVERecord?id=CVE-2026-31719 Référence CVE CVE-2026-43011 https://www.cve.org/CVERecord?id=CVE-2026-43011 Référence CVE CVE-2026-43033 https://www.cve.org/CVERecord?id=CVE-2026-43033 Référence CVE CVE-2026-43037 https://www.cve.org/CVERecord?id=CVE-2026-43037 Référence CVE CVE-2026-43038 https://www.cve.org/CVERecord?id=CVE-2026-43038 Référence CVE CVE-2026-43058 https://www.cve.org/CVERecord?id=CVE-2026-43058 Référence CVE CVE-2026-43071 https://www.cve.org/CVERecord?id=CVE-2026-43071 Référence CVE CVE-2026-43072 https://www.cve.org/CVERecord?id=CVE-2026-43072 Référence CVE CVE-2026-43073 https://www.cve.org/CVERecord?id=CVE-2026-43073 Référence CVE CVE-2026-43077 https://www.cve.org/CVERecord?id=CVE-2026-43077 Référence CVE CVE-2026-43078 https://www.cve.org/CVERecord?id=CVE-2026-43078 Référence CVE CVE-2026-43083 https://www.cve.org/CVERecord?id=CVE-2026-43083 Référence CVE CVE-2026-43114 https://www.cve.org/CVERecord?id=CVE-2026-43114 Référence CVE CVE-2026-43117 https://www.cve.org/CVERecord?id=CVE-2026-43117 Référence CVE CVE-2026-43123 https://www.cve.org/CVERecord?id=CVE-2026-43123 Référence CVE CVE-2026-43124 https://www.cve.org/CVERecord?id=CVE-2026-43124 Référence CVE CVE-2026-43125 https://www.cve.org/CVERecord?id=

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-017144LinuxのLinux Kernelにおける不特定の脆弱性

Linuxカーネルにおいて、以下の脆弱性が修正されました:x86-64で誤解を招く名前だった "__copy_user_nocache()" 関数の名称を変更しました。この関数は歴史的な理由から非常に不適切な名前が付けられていました。この関数は非キャッシュのユーザーコピーを謳っていましたが、実際にはそうではありません。宛先に対してのみ非順序的ストア(ソースには適用されません)を使用し、ソースと宛先のアクセス例外処理を行う特殊なメモリコピー処理ルーチンです。また、アライメントが取れていない宛先に対しては動作しますが、アライメントの取れていない部分(先頭や末尾)はx86ではワードまたはクアッドワードのみが非順序的になるため、非順序的ストアは使われません。例外処理を行うため、ユーザースペースアクセスに使用可能ですが、単独では使用できず、通常の "ユーザースペースアクセス開始" のロジックが必要です。通常、ユーザースペースアクセスはソースであり、非順序的ストアは宛先に使用されます。当初の意図は、マシンチェック例外を同期的に検出し優雅に処理する必要がある脆弱な永続メモリ宛先に対して非順序的ストアを行うことでした。そのため、この説明のない名前が付けられました。ユースケースの一つとしては、ユーザースペースから非キャッシュカーネルバッファへのコピーがありました。ただし、実際の使用者はこの意図されたケースとパフォーマンス向上のためにこの処理を使った異なるドライバーの混在でした。そのいくつかのドライバーはユーザーコピー版(STAC/CLAC含む)を例外処理を気にせずに非順序的宛先だけのために誤用していました。この問題に対し、まず名前をより適切に変更し、プロトタイプもより標準的に変更しました:呼び出し側が適切な変換を行っていない限りユーザーポインタは渡されず、引数のサイズは完全なsize_t型に変更しました(実際には一度に4GB以上コピーしませんが、引数のサイズをサイレントで切り捨てる理由はありません)。最後に、この正しく名前変更された関数をNTBコードで使用しました。NTBコードはこのインターフェースのユーザーコピー版(STAC/CLAC含む)を実際のユーザーコピーでないにもかかわらず誤用していました。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Linux: 06917f753547e6bba8a5d17f79971d1c071a70dd < 14b9194db4a28421a4dbe5d6e519efbaa7c5f3cd, 06917f753547e6bba8a5d17f79971d1c071a70dd < c6d4e0599e7e73abc04e2488dfeb7940c4039660, 06917f753547e6bba8a5d17f79971d1c071a70dd < d993e1723aa2a085aa0d72e70ea889031fc225b4, 06917f753547e6bba8a5d17f79971d1c071a70dd < efea91ad1729ff1853d7418e4d3bc27d085e72d0, 06917f753547e6bba8a5d17f79971d1c071a70dd < d187a86de793f84766ea40b9ade7ac60aabbb4fe, 4.2
Fixed
Linux: < 4.2, 6.12.83 ≤ 6.12.*, 6.18.24 ≤ 6.18.*, 6.19.14 ≤ 6.19.*, 7.0.1 ≤ 7.0.*, 7.1 ≤ *
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 5 May 2026 · Last source change 14 Jun 2026, 17:44 UTC · CWE not yet assigned

CVE recordCVE.org · 5.2
CVSS sourceNIST NVD
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-27378
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceUnavailable
NVD statusNVD modified after enrichment

Missing structured fields: CWE classification. Missing data is not evidence of low risk; review the primary advisory.

Material change intelligence

What changed after publication

View recent updates ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-43073 · cve.blacktree.nl