[CVE-2026-53205][MODERATE REGULAR] accel/ivpu: Add bounds checks for firmware log indices

[AL-KERNEL <alkernel@kernelcve.org>]

CVE: CVE-2026-53205
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: accel/ivpu: Add bounds checks for firmware log indices
Commit: 5961c703414048f46818be8bbb11075a9a63fb4e
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5961c703414048f46818be8bbb11075a9a63fb4e
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53205
Analysis date: Thu, 25 Jun 2026 20:33:54 -0400
ActionableScore: 4
ActionableScore lower bound: 2
Actionable bucket: Borderline manual review recommended / ordinary Moderate unless firmware or local trigger is credible
Manual review required: YES

Summary:
A firmware-supplied out-of-bounds log index in the Intel ivpu driver can cause invalid buffer reads during firmware log printing, with possible local DoS and limited diagnostic-output information disclosure depending on device and permission exposure.

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

The original Linux kernel CVE announcement for CVE-2026-53205 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53205

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: MODERATE REGULAR
Manual review required: YES

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

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AL-KERNEL CLASSIFICATION RESULT
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CVE-2026-53205	MODERATE	CHECK	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:H';CWE-125;CWE-129;*CWE-20;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:L';BEST CVSS score: '5.3';DESCR 'An out of bounds read in the Intel ivpu firmware log path may occur because firmware supplied read_index and write_index values are used as offsets into the log data buffer without sufficient bounds validation. If a faulty or malicious firmware instance places read_index or write_index outside data_size, fw_log_print_buffer can calculate invalid ranges and read past the firmware log buffer while printing diagnostic output. For the CVSS the PR:L is used for the paranoid score because triggering requires local access to the ivpu device or diagnostic path and influence over firmware log activity, but not necessarily full host administrator privileges in all deployments. The issue is not network reachable. Impact is mainly denial of service via invalid memory access, with limited confidentiality risk if adjacent memory is exposed through the log output. YES REQUIRES MANUAL CHECK';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline manual review recommended / ordinary Moderate unless firmware or local trigger is credible (with actual score 3)  SKIP CVE-2026-53205  SKIP The Fixes patch not applied yet, so unlikely that actual: 1fc1251149a76d3b75d7f4c94d9c4e081b7df6b4 YES  NO NO unknown 	MAYBE	WRITE OOB SIMPLEFIX LOG  LOWERED_FROM_HIGH_BASED_ON_GUESSCVSS  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=4
ActionableScoreLower=2

## 1. ActionableScore

* Conservative score: 2
* Paranoid score: 4
* Final recommended bucket: **Borderline manual review recommended / ordinary Moderate unless firmware or local trigger is credible**

## 2. Signal breakdown

Conservative signals:

* Firmware-mediated external influence: +1. The invalid indices come from firmware-controlled log metadata.
* Privileged kernel/device-management path: +1. The bug is in an accelerator driver firmware log path running in trusted kernel context.
* Confidentiality impact plausible: +1. An OOB read during log printing could potentially expose adjacent memory through diagnostic output.
* Rare AND difficult-to-reach subsystem/configuration: -1. This requires Intel ivpu hardware and the affected firmware log path.

Paranoid additional signals:

* Local unprivileged trigger: +1. Some deployments may allow non-root users to access accelerator workloads or paths that indirectly cause firmware log activity.
* Reliable kernel crash / strong DoS: +1. If the OOB index reaches unmapped or invalid memory during log printing, a kernel fault is plausible.

Not counted:

* No generic strong memory corruption. The patch indicates OOB read or invalid offset use, not OOB write, UAF, double-free, or controlled overwrite.
* No remote/network reachability.
* No strong LPE primitive demonstrated.

## 3. Reachability analysis

The direct source of invalid indices is firmware, not a network packet or ordinary syscall argument. A local user may be able to influence firmware activity through accelerator workloads, but reliable control of `read_index` or `write_index` is not demonstrated by the patch. Access to the actual log printing path may also depend on debugfs or driver diagnostics permissions, which often require elevated privileges. Namespaces do not obviously make this broadly reachable unless the ivpu device is delegated into a container.

## 4. Severity interpretation

This behaves more like a low-to-moderate firmware-mediated OOB read than an Important-class kernel memory corruption issue. Theoretical impact includes kernel crash and limited memory disclosure through logs, but the patch does not support arbitrary write, object lifetime corruption, or a credible privilege escalation primitive. Manual review is useful mainly to confirm who can trigger log printing and whether unprivileged accelerator workloads can influence firmware log indices.

## 5. One-sentence report phrase

A firmware-supplied out-of-bounds log index in the Intel ivpu driver can cause invalid buffer reads during firmware log printing, with possible local DoS and limited diagnostic-output information disclosure depending on device and permission exposure.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Reason: explicit OOB buffer access exists in a firmware-fed kernel driver path, but exploitation appears constrained and no strong memory corruption or LPE primitive is shown.

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

Patch: accel/ivpu: Add bounds checks for firmware log indices
Commit: 5961c703414048f46818be8bbb11075a9a63fb4e
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5961c703414048f46818be8bbb11075a9a63fb4e

Commit description:

Add validation that read and write indices in the firmware log buffer
are within valid bounds (< data_size) before using them. If
out-of-bounds indices are encountered (from firmware), clamp them to
safe values instead of proceeding with invalid offsets.

This prevents potential out-of-bounds buffer access when firmware
supplies invalid log indices.

Fixes: 1fc1251 ("accel/ivpu: Refactor functions in ivpu_fw_log.c")
Cc: stable@vger.kernel.org # v6.18+
Signed-off-by: Andrzej Kacprowski <andrzej.kacprowski@linux.intel.com>
Reviewed-by: Karol Wachowski <karol.wachowski@linux.intel.com>
Signed-off-by: Karol Wachowski <karol.wachowski@linux.intel.com>
Link: https://patch.msgid.link/20260529115842.135378-1-andrzej.kacprowski@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/accel/ivpu/ivpu_fw_log.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=5961c703414048f46818be8bbb11075a9a63fb4e

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

The original Linux kernel CVE announcement for CVE-2026-53205 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53205

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:H/PR:L/UI:N/S:U/C:L/I:N/A:L
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:H
  The Best / paranoid CVSS score: 5.3

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: 2
  Paranoid ActionableScore: 4

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: MODERATE
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): MODERATE REGULAR

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).