[CVE-2026-80693][MODERATE 7.0] idpf: bound interrupt-vector register fill to the allocated array [ Upstream

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

CVE: CVE-2026-80693
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: idpf: bound interrupt-vector register fill to the allocated array [ Upstream
Commit: 41bb8748124d0d8ee5d8e1eace9dfbc874bc9564
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=41bb8748124d0d8ee5d8e1eace9dfbc874bc9564
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80693
Analysis date: Fri, 28 Aug 2026 07:32:46 -0400
ActionableScore: 8
ActionableScore lower bound: 5
Actionable bucket: Strong Important candidate / Actionable Moderate at minimum
Manual review required: YES

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-80693 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80693

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: 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
======================================================================

CVE-2026-80693	MODERATE	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H';*CWE-787;*CWE-20;CWE-129;Other CVSS 'AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '8.8';DESCR 'An out-of-bounds write can occur in the idpf interrupt vector register setup path because idpf_get_reg_intr_vecs filled the caller allocated reg_vals array using per chunk num_vectors from the VIRTCHNL2_OP_ALLOC_VECTORS reply without enforcing the total array capacity. A malicious or compromised PF, firmware, or hypervisor device model can return a reply where num_allocated_vectors is smaller than the sum of the per chunk vector counts, causing struct idpf_vec_regs entries to be written past the kmalloc allocation. For the CVSS the PR:N is used because no local privileges are required inside the victim OS when the attacker controls the device side of the virtchnl control path. The issue is not reachable through normal packet traffic and is better modeled as AV:A because the attacker must control an adjacent device or virtual device control plane endpoint. Impact is at least denial of service via kernel memory corruption, and the paranoid score uses C:H/I:H/A:H because the bug is a kernel heap out-of-bounds write with attacker influenced data.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 7)	YES	REMOTE WRITE KASAN OOB NETWORK HARDWARE KPANIC  KPANIC INCREASED_TO_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFDH	YES	NO	checked

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

ActionableScore=8
ActionableScoreLower=5

1. ActionableScore
* Conservative score: 5
* Paranoid score: 8
* Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**::

2. Signal breakdown
* Firmware-mediated external influence: +1. The malformed VIRTCHNL2_OP_ALLOC_VECTORS reply comes from PF, firmware, or a hypervisor device model rather than ordinary packet traffic.
* Memory corruption, Strong corruption primitive: +2. The patch prevents a KASAN-confirmed slab out-of-bounds write past the reg_vals kmalloc allocation.
* Privileged kernel/device-management memory corruption path: +1. The corruption occurs in idpf interrupt-vector register initialization, a trusted driver/device-management path.
* Reliable kernel crash / strong DoS: +1. The described primitive is sufficient for KASAN splat and likely kernel crash or driver failure.
* Integrity impact plausible: +1 in conservative score. A kernel heap OOB write can corrupt adjacent kernel objects, though target selection is not demonstrated.
* Privilege escalation plausible: +2 in paranoid score. This is not proven, but a kernel heap OOB write with attacker-influenced device reply data is a defensible manual-review LPE candidate.
* Confidentiality impact plausible: +1 in paranoid score. Not demonstrated, but possible if heap corruption becomes exploitable.
* No attacker-controlled target selection or constrained overwrite uncertainty: -1. The write payload and target are constrained by struct idpf_vec_regs layout and adjacent heap placement.

3. Reachability analysis
The realistic attacker is a malicious or compromised PF, firmware, or hypervisor device model that can influence the idpf virtchnl control-plane reply. This is not remotely reachable through normal Ethernet packet traffic, so AV:A is more appropriate than AV:N. No local privileges inside the victim OS are needed if the attacker controls the device side of the virtchnl path, so PR:N is reasonable for the device-mediated threat model. The issue depends on systems using the idpf driver and the affected interrupt-vector initialization path, so exposure is narrower than core networking but important in virtualized or device-mediated deployments.

4. Severity interpretation
This is more than ordinary Moderate because the primitive is an explicit kernel heap out-of-bounds write, not only a warning, leak, or validation cleanup. Conservative handling is Actionable Moderate because exploitation conditions require a malicious device-side control plane and the overwrite appears constrained. Paranoid handling is a Strong Important candidate because firmware or hypervisor supplied data can drive a slab OOB write in a trusted kernel driver path, and such bugs can become privilege or isolation boundary issues after deeper analysis.

5. One-sentence report phrase
An idpf interrupt-vector setup bug allows a malicious PF, firmware, or hypervisor device model to return inconsistent vector counts and cause a slab out-of-bounds write past the reg_vals allocation, with at least kernel crash impact and a defensible paranoid concern for broader kernel memory corruption.

6. Manual review recommendation
MANUAL CHECK REQUIRED. YES REQUIRES MANUAL CHECK.
Reason: explicit kernel heap OOB write in a device-mediated trusted driver path, with attacker-influenced control-plane data and possible impact beyond DoS.

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

Patch: idpf: bound interrupt-vector register fill to the allocated array [ Upstream
Commit: 41bb8748124d0d8ee5d8e1eace9dfbc874bc9564
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=41bb8748124d0d8ee5d8e1eace9dfbc874bc9564

Changed files:
  drivers/net/ethernet/intel/idpf/idpf_dev.c
  drivers/net/ethernet/intel/idpf/idpf_vf_dev.c
  drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
  drivers/net/ethernet/intel/idpf/idpf_virtchnl.h

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=41bb8748124d0d8ee5d8e1eace9dfbc874bc9564

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

The original Linux kernel CVE announcement for CVE-2026-80693 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80693

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:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
  The Best / paranoid CVSS vector: AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 8.8

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: 5
  Paranoid ActionableScore: 8

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: YES
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).