[CVE-2026-98911][MODERATE 7.0] dpaa2-switch: fix the error path in dpaa2_switch_rx() [ Upstream

[CVE-2026-98911][MODERATE 7.0] dpaa2-switch: fix the error path in dpaa2_switch_rx() [ Upstream

[AL-KERNEL]

CVE: CVE-2026-98911
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: dpaa2-switch: fix the error path in dpaa2_switch_rx() [ Upstream
Commit: 791068c962469af0090e1a1ee63657fb9eef40db
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=791068c962469af0090e1a1ee63657fb9eef40db
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98911
Analysis date: Tue, 27 Oct 2026 03:41:54 -0400
ActionableScore: 4
ActionableScore lower bound: unknown
Actionable bucket: Borderline / manual review recommended
Manual review required: YES

Summary:
An adjacent malformed frame can steer DPAA2 switch RX error handling into TX-only cleanup, causing `dev_kfree_skb()` to consume an invalid annotation pointer and plausibly crash the kernel.

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

The original Linux kernel CVE announcement for CVE-2026-98911 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98911

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.

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

CVE-2026-98911	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-98911 CHECK WITH IMPACT FROM ORIG NN LOW | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=3 LEGACY=MODERATE_KPANIC RESULT=SAME V39_AEGIS_ONE_STEP_UP=MODERATE->MODERATE_KPANIC (final reconciliation agrees; DECISION: both MODERATE_KPANIC)	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H';CWE-763;CWE-843;CWE-754;Other CVSS 'AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7.5';DESCR 'The dpaa2 switch RX error path incorrectly used a TX descriptor cleanup routine that expects a valid skb pointer in the software annotation area. An RX descriptor does not provide that invariant, so dev_kfree_skb may receive an invalid or stale pointer and cause a kernel crash. A malformed VLAN frame may help reach the error after skb creation, while other branches depend on invalid FD metadata or allocation failure, so reliable packet control of the invalid pointer is not established. For the CVSS the PR:N value is selected because an adjacent sender does not need a local account or device privileges to submit frames to an exposed switch port. The base impact is denial of service. The paranoid impact considers a possible invalid free and resulting kernel memory corruption, but no controlled arbitrary write or reliable privilege escalation primitive is proven. Automated impact decision path. The original SimpleNet classifier selected MODERATE_KPANIC. The primary LLM estimated paranoid CVSS 7.5 and the production ActionableScore returned 4 with recommendation Borderline / manual review recommended. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were CVSS and initial triage stage MODERATE_KPANIC to MODERATE_KPANIC because the CVSS score, vector or bug class threshold rule was applied. KP and FD specialist checks stage MODERATE_KPANIC to MODERATE because KP specialist did not establish a qualifying panic. final reconciliation stage MODERATE to MODERATE_KPANIC because the cross model evidence reconciliation rule was applied. The legacy KP specialist produced a review artifact and its decision was processed by the applicable KP rules. The legacy FD or DH downgrade specialist has no review artifact for this run. Exact triggered rule markers were INCREASED_TO_MODERATE7_BASED_ON_GUESSCVSS and DECREASED_TO_MODERATEREG_BASED_ON_FALSEPOSCHECKOFKP and V39_AEGIS_ONE_STEP_UP and MANUAL_REVIEW_REQUIRED. The independent weaker Aegis shadow evaluated CVSS 3.1 and ActionableScore 3 with primitive class CLASS_B and manual review REQUIRED. Its independently reconciled impact was MODERATE_KPANIC. Cross model aggregation changed the production result under an enabled evidence gated merge rule. The final reported impact is MODERATE_KPANIC.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended (with actual score 4)	MAYBE	REMOTE LOCK INIT SIMPLEFIX ERRORPATH NETWORK SKB HARDWARE LINUS MEMORY  INCREASED_TO_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_MODERATEREG_BASED_ON_FALSEPOSCHECKOFKP KPANIC V39_AEGIS_ONE_STEP_UP MANUAL_REVIEW_REQUIRED	-	-	checked

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

ActionableScore=4
PrimitiveClass=CLASS_B
RealUAF=NO
HostAdminRequired=NO
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
RequiresHostUID0=NO
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO

1. ActionableScore

* Raw base score: 4.
* Conservative score: 4; no floor or cap applied.
* Raw paranoid score: 4.
* Paranoid score: 4; stronger corruption would require unsupported control over the annotation pointer or a demonstrated non-crash mutation.
* Final recommended bucket: **Borderline / manual review recommended**::

2. Signal breakdown

* +2 remote/adjacent network reachability: an adjacent sender can supply frames to an exposed DPAA2 switch port; malformed VLAN input plausibly reaches the post-SKB error path.
* +1 weak/indirect lifetime corruption: an RX descriptor is incorrectly interpreted using TX cleanup semantics, and annotation data is passed as an `skb` pointer to `dev_kfree_skb()`.
* +1 plausible kernel crash: dereferencing or freeing that invalid pointer can fault.
* No RealUAF: the pointer may be invalid or stale, but no specific previously freed object or post-lifetime use is established.
* No controlled reclaim, attacker-selected pointer, arbitrary write, disclosure, or LPE is shown.
* No extra availability point: it would duplicate the same crash.
* NEW52/B5-R does not apply: there is no confirmed retry-accumulated heap OOB write.
* NEW53/B3-PENDING does not apply: no shared/file-backed write is shown.
* No authorization bypass exists; B4 pending profiles do not apply.

3. Reachability analysis

The credible actor is an adjacent network sender without local credentials or host-administrator powers. The malformed-VLAN branch occurs after SKB creation and can enter the incorrect cleanup path. Other error branches depend on invalid FD metadata or allocation failure and are less attacker-controlled. DPAA2 hardware and an exposed switch port are deployment prerequisites, but no namespace capability, UID 0, or host administrative operation is required of the packet sender. Trigger reliability and control over the bogus annotation pointer remain unresolved; no narrow race is involved.

4. Primitive and severity reading

The primitive is a wrong-type cleanup operation: RX frame storage lacking a valid TX annotation `skb` pointer is consumed by `dev_kfree_skb()`. This is CLASS_B wrong-object/lifetime handling, but the demonstrated consequence is predominantly an invalid-pointer crash. A useful refcount mutation or invalid free may occur if the garbage pointer happens to reference plausible storage, but that is not established or attacker-directed. Consequently, Important-grade leverage is not shown, and constrained crash-focused downgrade remains allowed.

5. One-sentence report phrase

An adjacent malformed frame can steer DPAA2 switch RX error handling into TX-only cleanup, causing `dev_kfree_skb()` to consume an invalid annotation pointer and plausibly crash the kernel.

6. Manual review advice

MANUAL CHECK RECOMMENDED

Confirm whether receive-buffer annotation bytes can be influenced into a plausible `skb` pointer and whether malformed VLAN frames reliably reach the affected branch.

7. Call-site confidence

Call-site confidence: high

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

Patch: dpaa2-switch: fix the error path in dpaa2_switch_rx() [ Upstream
Commit: 791068c962469af0090e1a1ee63657fb9eef40db
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=791068c962469af0090e1a1ee63657fb9eef40db

Changed files:
  drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.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=791068c962469af0090e1a1ee63657fb9eef40db

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

The original Linux kernel CVE announcement for CVE-2026-98911 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98911

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:H/PR:N/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 7.5

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: unknown
  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: 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).