[CVE-2026-72089][MODERATE 7.0] accel/ivpu: Reject firmware log with size smaller than header commit ddb44baed257560f192b145ed36cf8c0a412de47 upstream.

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

CVE: CVE-2026-72089
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: accel/ivpu: Reject firmware log with size smaller than header commit ddb44baed257560f192b145ed36cf8c0a412de47 upstream.
Commit: 5592a207e158b738d9c1d27f208dbbea13ae7606
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5592a207e158b738d9c1d27f208dbbea13ae7606
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72089
Analysis date: Sun, 16 Aug 2026 01:47:52 -0400
ActionableScore: 5
ActionableScore lower bound: 4
Actionable bucket: Actionable Moderate at minimum
Manual review required: NO

Summary:
A firmware log parsing flaw in the Intel ivpu driver can underflow the computed log data size when log size is smaller than header size, causing out-of-bounds reads during log printing or an infinite loop for zero-size logs, with local DoS and possible information disclosure impact.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-72089 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72089

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 7.0
Manual review required: NO

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-2026-72089	MODERATE	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H';CWE-191;CWE-125;*CWE-835;*CWE-20;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:H';BEST CVSS score: '6.3';DESCR 'A firmware log parsing bug in the Intel ivpu accelerator driver can underflow data_size when a firmware supplied log size is smaller than header_size. The resulting near U32_MAX length can make fw_log_print_lines read beyond the real firmware log data region in the BO and a zero size log can also make the caller loop on the same header forever. For the CVSS the PR:L is used for the paranoid score because a local user with access to the accel device may be able to trigger firmware log handling through device workloads or debug paths, while direct control of malformed firmware log contents is not always guaranteed. The issue is not network reachable and requires local interaction with the affected accelerator device. Impact is at least local denial of service via kernel crash or hang. The worst still defensible impact includes high confidentiality risk from out-of-bounds kernel reads that may be printed through firmware log output, but no integrity impact is assigned because the patch supports an out-of-bounds read and loop condition rather than a write primitive.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 5)  SKIP CVE-2026-72089 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: d4e4257afa6ed5205eda993180401fc2c20e4b60 YES  NO NO unknown 	MAYBE	OOB LOG IMPROVEONLY  DECREASED_TO_MODERATEREG_BASED_ON_FALSEPOSCHECKOFKP	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=5
ActionableScoreLower=4

## 1. ActionableScore

* Conservative score: 4
* Paranoid score: 5
* Final recommended bucket: **Actionable Moderate at minimum**::

## 2. Signal breakdown

Conservative signals:

* Firmware-mediated external influence: +1. The malformed log size is supplied by firmware or firmware-controlled tracing data.
* Local unprivileged trigger: +1. A local user with access to the ivpu accel device may be able to trigger firmware log handling through workloads or debug paths, although direct control over malformed log contents is uncertain.
* Reliable kernel crash / strong DoS: +1. The integer underflow can make fw_log_print_lines read far past the real BO log data region, and size 0 can cause an infinite loop on the same header.
* Confidentiality impact plausible: +1. The out-of-bounds read is in a log printing path, so adjacent kernel or BO memory may be exposed through firmware log output.
* Privileged kernel/device-management memory corruption path: +1. This is a firmware-fed accelerator driver path parsing trusted kernel-visible BO contents.
* Rare AND difficult-to-reach subsystem/configuration: -1. The issue requires Intel ivpu hardware and firmware log handling, so exposure is narrower than core kernel paths.

Paranoid additional signal:

* Availability impact realistic: +1. The zero-size case can cause a persistent loop, and the large underflowed read may cause a strong local availability failure beyond a simple validation warning.

No signals awarded:

* No remote reachable signal. This is not a network protocol path.
* No strong LPE signal. The patch shows OOB read and infinite loop, but not UAF reclaim, write-after-free, arbitrary write, type confusion, callback control, or refcount takeover.
* No integrity signal. The demonstrated primitive is read-only OOB plus loop, not a write primitive.

## 3. Reachability analysis

The likely trigger is local interaction with an affected Intel ivpu accelerator device, with malformed firmware log metadata coming from firmware-visible tracing buffers. In typical systems, accel devices may be exposed to local users through device nodes or render-style access groups, so PR:L is a reasonable paranoid interpretation. If the product restricts ivpu access to root or a trusted service only, the practical score would be lower.

Namespaces and containers only matter if the ivpu device node is passed through or delegated. Without device access, an unprivileged container should not be able to trigger the path. The bug is not default-reachable on systems without Intel ivpu hardware, enabled driver support, and firmware log processing.

Call-site confidence: high. The commit message identifies the downstream computation in fw_log_print_buffer and the later read in fw_log_print_lines, and the patch directly fixes the missing size >= header_size invariant.

## 4. Severity interpretation

This is stronger than an ordinary validation bug because the missing check produces a concrete integer underflow, an out-of-bounds read, and a possible infinite loop. It behaves like an actionable Moderate issue: local or firmware-mediated, hardware-specific, but involving kernel-context OOB reads and reliable DoS potential.

It does not reach a strong Important classification on the available evidence because there is no demonstrated write primitive, UAF, object replacement, type confusion, or practical privilege escalation path. The theoretical concern is information disclosure from out-of-bounds log printing, while the realistic impact is local DoS plus possible limited kernel memory disclosure.

## 5. One-sentence report phrase

A firmware log parsing flaw in the Intel ivpu driver can underflow the computed log data size when log size is smaller than header size, causing out-of-bounds reads during log printing or an infinite loop for zero-size logs, with local DoS and possible information disclosure impact.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Manual review is recommended because this is a firmware-influenced kernel OOB read in a log printing path, which may expose adjacent memory depending on BO layout and log visibility. It is not automatically Important without evidence of a write primitive or LPE path, but it should not be auto-closed as a trivial Moderate.

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UPSTREAM PATCH SUMMARY
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Patch: accel/ivpu: Reject firmware log with size smaller than header commit ddb44baed257560f192b145ed36cf8c0a412de47 upstream.
Commit: 5592a207e158b738d9c1d27f208dbbea13ae7606
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5592a207e158b738d9c1d27f208dbbea13ae7606

Commit description:

fw_log_from_bo() validates the tracing buffer header_size and that the
log fits within the BO, but never checks that log->size is at least
log->header_size. fw_log_print_buffer() then computes:

  u32 data_size = log->size - log->header_size;

which underflows to a near-U32_MAX value when firmware reports a log whose
size is smaller than its header. That huge data_size defeats the
log_start/log_end bounds clamps added by commit dd1311bcf0e6 ("accel/ivpu:
Add bounds checks for firmware log indices"), so fw_log_print_lines() reads
far past the small real data region of the BO. A size of 0 also makes
fw_log_from_bo() advance the offset by 0, causing the callers to loop
forever on the same header.

Reject logs whose size is smaller than the header (which also rejects
size == 0).

Fixes: d4e4257afa6e ("accel/ivpu: Add firmware tracing support")
Cc: stable@vger.kernel.org
Signed-off-by: Jhonraushan <raushan.jhon@gmail.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/20260715074206.867712-1-raushan.jhon@gmail.com
Signed-off-by: Raushan Patel <raushan.jhon@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat -rw-r--r-- drivers/accel/ivpu/ivpu_fw_log.c 4

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=5592a207e158b738d9c1d27f208dbbea13ae7606

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

The original Linux kernel CVE announcement for CVE-2026-72089 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72089

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:H
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H
  The Best / paranoid CVSS score: 6.3

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: 4
  Paranoid ActionableScore: 5

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 7.0

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).