[CVE-2026-74419][LOW] accel/amdxdna: Adjust size for copy_to_user() [ Upstream

[CVE-2026-74419][LOW] accel/amdxdna: Adjust size for copy_to_user() [ Upstream

[AL-KERNEL]

CVE: CVE-2026-74419
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: accel/amdxdna: Adjust size for copy_to_user() [ Upstream
Commit: 097e57195ef813735c8b714d6503bf3ad0742515
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=097e57195ef813735c8b714d6503bf3ad0742515
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74419
Analysis date: Sat, 15 Aug 2026 19:46:07 -0400
ActionableScore: 2
ActionableScore lower bound: 1
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
amdxdna query ioctls did not consistently limit copy_to_user() and copy_from_user() sizes to the caller-provided buffer size, allowing a local device user to receive or overwrite more userspace data than declared, but without evidence of kernel memory corruption or privilege escalation.

======================================================================
ABOUT THIS REPORT
======================================================================

The original Linux kernel CVE announcement for CVE-2026-74419 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74419

The original announcement does not normally provide a security severity
estimate, CVSS assessment, or enough information to determine whether the
reported kernel bug represents a practically relevant security issue.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin. It combines
an autonomous classifier with LLM-assisted technical analysis and a
separate ActionableScore mechanism.

The purpose of this report is to prioritize Linux kernel CVEs before
manual review, identify cases that require prompt investigation, and
support automatic closure of issues that are unlikely to have meaningful
security impact.

Published priority for this report: LOW
Manual review required: NO

A detailed explanation of the methodology and priority rules is included
at the end of this message.

======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================

CVE-2026-74419	LOW	CHECK WITH IMPACT FROM ORIG NN MODERATE	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N';CWE-805;*CWE-787;*CWE-20;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N';BEST CVSS score: '4.4';DESCR 'amdxdna query ioctls could copy more data to user space than the application declared in args buffer_size. Several query paths used sizeof kernel response structures or firmware response sizes for copy_to_user() instead of limiting the copy to the user supplied buffer size, so a small buffer could receive a partial overwrite beyond the intended application buffer. For the CVSS the PR:L value is used because triggering requires a local process with access to the amdxdna DRM accel device and its ioctl interface. The issue is not network reachable. Impact is mainly a local user space memory corruption or information exposure concern for the calling process, not kernel memory corruption. No plausible direct privilege escalation path is visible from this patch alone.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2)  SKIP CVE-2026-74419 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	PRINTF-TTY MEMORY  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	-	-	checked

======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================

ActionableScore=2
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate / Low-like**::

## 2. Signal breakdown

Triggered signals:

* Local unprivileged or low-privileged trigger: +1
  The issue is reachable through amdxdna DRM accel query ioctls by a local process that can open the device node. In typical deployments this is PR:L rather than PR:H, depending on render node or device ACL access.

Paranoid-only signal:

* Confidentiality impact plausible: +1
  Some query paths copy kernel or firmware-derived response data to user space using sizes not consistently bounded by the caller-declared buffer size. This may expose more driver or device query data to the same calling process than its declared buffer intended, but no cross-user or privileged-kernel disclosure primitive is shown.

Not awarded:

* Generic memory corruption: +0
  The writes are copy_to_user() into user address space, not kernel memory corruption.

* Constrained kernel buffer overwrite: +0
  No kernel buffer overwrite is shown.

* Privilege escalation plausible: +0
  No UAF, refcount misuse, type confusion, arbitrary write, callback control, page-cache corruption, or security-boundary bypass is visible.

* Reliable kernel crash / strong DoS: +0
  The likely failure mode is EFAULT or local userspace memory overwrite in the caller, not a reliable kernel crash.

* Broad/default exposure: +0
  amdxdna is hardware and driver dependent, not a broad default kernel attack surface.

* Rare/device-specific exposure: not applied as a hard penalty
  The subsystem is hardware-specific, but it remains reachable through ordinary local device ioctls when the device exists.

## 3. Reachability analysis

A local process with access to the amdxdna DRM accel device can trigger the affected query paths. Namespaces do not by themselves make the issue remotely reachable, but container or sandbox exposure depends on whether the device node is passed through and accessible.

The path is not network reachable. It is also not a generic default kernel interface because it depends on AMD XDNA/NPU hardware and the amdxdna driver being present and exposed to userspace.

Realistic exploitation conditions are limited. The bug concerns inconsistent use of user-provided buffer sizes in copy_to_user() and copy_from_user() paths. Since copy_to_user() writes only to the caller's userspace address range, the patch does not show a kernel memory corruption primitive or a practical privilege escalation chain.

## 4. Severity interpretation

This behaves more like an ordinary Moderate or Low-like local UAPI bounds-handling issue, not an Important-class kernel vulnerability.

Theoretical concern exists because user/kernel copy length mismatches can sometimes hide information disclosure or memory corruption issues. In this patch, however, the affected copies are bounded by kernel/user access checks and target the calling process memory. The visible impact is mainly incorrect partial-buffer handling, possible overwrite beyond the application-declared logical buffer inside the same process, or exposure of driver/device query response data to the same caller.

There is no supported evidence of kernel memory corruption, cross-process data exposure, privilege escalation, or reliable system-wide DoS.

## 5. One-sentence report phrase

amdxdna query ioctls did not consistently limit copy_to_user() and copy_from_user() sizes to the caller-provided buffer size, allowing a local device user to receive or overwrite more userspace data than declared, but without evidence of kernel memory corruption or privilege escalation.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

The patch is a local device-specific UAPI size-handling fix with no demonstrated kernel corruption primitive, no network reachability, no strong DoS, and no plausible LPE path from the supplied diff.

======================================================================
UPSTREAM PATCH SUMMARY
======================================================================

Patch: accel/amdxdna: Adjust size for copy_to_user() [ Upstream
Commit: 097e57195ef813735c8b714d6503bf3ad0742515
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=097e57195ef813735c8b714d6503bf3ad0742515

Changed files:
  drivers/accel/amdxdna/aie2_error.c
  drivers/accel/amdxdna/aie2_message.c
  drivers/accel/amdxdna/aie2_pci.c

Diff excerpt:

Not included in this email. See the upstream URL for the full patch.

Full patch:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=097e57195ef813735c8b714d6503bf3ad0742515

======================================================================
DETAILED REPORT METHODOLOGY
======================================================================

The original Linux kernel CVE announcement for CVE-2026-74419 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74419

The original CVE announcement normally does not include a security-level
estimate. In particular, it may not contain a CVSS assessment, an impact
level, or enough information to determine whether the reported bug is a
practically relevant security issue. One purpose of this parallel CVE list
is to provide that missing technical and prioritization information.

The original goal of the AL-KERNEL project was to prioritize Linux kernel
CVE analysis automatically before manual review. The system can also help
identify non-security issues that may be suitable for automatic closure.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin.

The first analysis stage combines an autonomous classifier with additional
LLM-based analysis. The autonomous classifier runs locally on a CPU and is
based on a backpropagation neural network. Together, these mechanisms
produce a technical vulnerability description, identify likely weakness
types, estimate CVSS severity, and provide input for ActionableScore.

Two CVSS estimates are retained because incomplete kernel vulnerability
information often permits more than one defensible interpretation:

  Conservative CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
  The Best / paranoid CVSS score: 4.4

The conservative vector represents a lower-impact interpretation.
The Best/paranoid vector intentionally represents a plausible upper-bound
interpretation and should not automatically be treated as demonstrated
real-world impact.

CVSS may also need to be adjusted for a particular Linux deployment,
because actual reachability, privileges, enabled kernel configuration,
hardware, namespaces, exposed device nodes, and other environmental
conditions can differ significantly between systems.

A separate ActionableScore mechanism evaluates practical remediation
urgency. Its analysis may include reachability, attack prerequisites,
subsystem exposure, memory-corruption characteristics, denial-of-service
reliability, and possible confidentiality, integrity, or
privilege-escalation impact.

  Conservative ActionableScore: 1
  Paranoid ActionableScore: 2

The final base severity is taken directly from the second tab-separated
field of the AL-KERNEL classification result. ActionableScore does not
replace or independently override that final AL-KERNEL decision, and
if ActionableScore adjusted impact level of ALKERNEL, then you would see
self-readable flags above like INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7.

For an AL-KERNEL result of MODERATE, this report uses the following
additional presentation split:

  ActionableScore below 5   -> MODERATE REGULAR
  ActionableScore 5 or more -> MODERATE 7.0

The distinction between MODERATE REGULAR and MODERATE 7.0 makes it
possible to identify Moderate issues that should receive manual analysis
and fixes before lower-priority MODERATE REGULAR issues. In many cases,
MODERATE REGULAR fixes may wait for a later rebase or routine update.

There is one override in which MODERATE REGULAR becomes MODERATE 7.0
even when the ActionableScore is below 5. When the AL-KERNEL result
contains the KPANIC flag, a MODERATE result is always presented as
MODERATE 7.0. The KPANIC flag selected with few regexps without
usage of AI at all, so it helps to detect cases when Kernel Crash happens
and similar (to filter False-Negative results from the LLM usage).

KPANIC indicates that a reliable kernel crash, kernel panic, or similarly
serious kernel availability impact was identified by the classification
workflow.

AL-KERNEL base severity for this report: LOW
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): LOW

These results are intended to support engineering triage. They are
machine-generated estimates, and cases marked for manual review should
be validated by a human security engineer before final disposition.
For more info read docs linked from here: https://kernelcve.org/
(and you can submit you own patch there to generate such a report
for non-existant CVE-id yet).

Note that in many cases this AI tool selects higher severity, than
real is (means you can expect Importants instead of Moderate 7.0 or
Moderates 7.0 instead of regular Moderates). If you see such cases,
please use reply email interface to add additional manual analyses
info to this particular CVE.
And please, please, let me know when you see Lows instead of Importants
or Important instead of Low (because particular for such cases I
need to tune this AI tool to make it better for this one and next similar).
My contact email for such notifications is alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).