[CVE-2026-98296][MODERATE REGULAR] Bluetooth: btintel_pcie: validate TX skb length in send_sync [ Upstream

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

CVE: CVE-2026-98296
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: Bluetooth: btintel_pcie: validate TX skb length in send_sync [ Upstream
Commit: 84f353256e170dc4865d45007d1bc446ed566da7
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=84f353256e170dc4865d45007d1bc446ed566da7
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98296
Analysis date: Sat, 10 Oct 2026 22:51:08 -0400
ActionableScore: 1
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-98296 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98296

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: NO

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

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

CVE-2026-98296	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-98296 CHECK WITH IMPACT FROM ORIG NN LOW | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=1 LEGACY=MODERATE RESULT=DIFF (independent Legacy and Aegis differ; FINAL: MODERATE, Aegis: MODERATE_KPANIC)	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:H/A:H';*CWE-787;CWE-120;*CWE-20;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '7';DESCR 'btintel_pcie_send_sync did not validate skb length before the transmit path copied skb data into a fixed 4096 byte DMA slot. If an oversized skb can reach this function, the unchecked copy can write beyond the DMA buffer and may cause kernel memory corruption, a crash, or potentially privilege escalation. The currently described external transmit path already rejects oversized packets, and the commit presents this check as protection against a future caller. Therefore a reliable trigger from an unprivileged user is not established by the supplied code. For the CVSS the PR:L value in the paranoid score assumes that a locally running user with limited Bluetooth access can reach an overlooked synchronous transmit path without full administrative control. The issue is not shown to be remotely triggerable over a network or directly through a Bluetooth radio peer. Impact is at least denial of service if the overflow is reached, while the concrete out of bounds write justifies manual review for possible confidentiality and integrity impact.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1)	MAYBE	OOB SIMPLEFIX ERRORPATH SKB DMAorINTERRUPT IMPROVEONLY LINUS PACKET  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4	-	-	checked

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

ActionableScore=1
PrimitiveClass=CLASS_B
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
RequiresHostUID0=UNKNOWN
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO

1. ActionableScore

* Raw conservative score: 1
* Conservative score: 1
* Raw paranoid score: 1
* Paranoid score: 1
* No floor or cap was applied.
* Final recommended bucket: **Ordinary Moderate**::

2. Signal breakdown

* +1 Constrained kernel buffer overwrite. An oversized skb reaching `btintel_pcie_send_sync()` would be copied into a fixed 4096-byte DMA slot without a local length check.
* No strong-corruption bonus. The destination is a fixed DMA slot, and current attacker control over the payload, overwrite extent, adjacent target, or calling path is not established.
* No crash point. The commit establishes possible overflow but does not report an Oops, panic, device failure, or host-wide DoS.
* No local-unprivileged or remote-reachability point. The visible external transmit path already rejects oversized packets, while another attacker-accessible caller is not identified.
* No privilege penalty. Host-admin privilege is not established, but below-host-admin reachability is also not established.
* No C/I, controlled reclaim, arbitrary write, callback influence, LPE, or repeated-lifetime signal.
* B5-R does not apply. There is no retry-accumulated index or offset, attacker-influenced retry sequence, or later consumption of retry-corrupted structured state.
* B3-PENDING does not apply. No shared or file-backed storage write is shown.
* B4-PENDING does not apply. No authorization decision or mandatory security-state check is involved.

3. Reachability analysis

The supplied patch does not identify an existing caller capable of passing an oversized skb to `btintel_pcie_send_sync()`. It explicitly states that oversized packets are already rejected by `btintel_pcie_send_frame()` and describes the missing check as hazardous to a future caller. Consequently, ordinary-user, namespace-capability, delegated-service, host-administrator, and Bluetooth-radio reachability remain unresolved.

The Intel PCIe Bluetooth device and driver are prerequisites, but hardware-specific code alone does not justify a rarity penalty. No race, retry sequence, prior privileged setup, or direct network trigger is established.

4. Primitive and severity interpretation

The exact conditional primitive is a sequential heap or DMA-slot OOB write caused by copying `skb->len` bytes into a fixed-size transmit buffer. It is fixed-target storage rather than a UAF, repeated release, controlled reclaim, or active-object replacement.

The overwrite mechanics justify constrained CLASS_B classification, but the supplied evidence does not establish that any current attacker-invocable path can satisfy the oversized-length condition. The demonstrated patch-supported consequence is therefore a latent corruption condition, not a confirmed exploitable crash or integrity violation.

ImportantCandidate is NO because attacker reachability and meaningful exploitation leverage are both unresolved. AutoDowngradeAllowed is YES because there is no established active attack path, security-boundary violation, or strong unresolved corruption primitive. Operational severity is Low-like unless call-site analysis identifies a current path that can construct and submit an oversized skb.

5. One-sentence report phrase

A missing length check could let an oversized synchronous Intel PCIe Bluetooth transmit skb overflow a fixed DMA slot, but the supplied evidence identifies no current attacker-reachable caller because the existing external transmit path already rejects oversized packets.

6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Review all current `btintel_pcie_send_sync()` callers and skb construction bounds. Escalation is warranted only if an existing attacker-invocable path can supply an oversized skb and the resulting overwritten DMA-adjacent state is subsequently consumed.

7. Call-site confidence

Call-site confidence: medium

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

Patch: Bluetooth: btintel_pcie: validate TX skb length in send_sync [ Upstream
Commit: 84f353256e170dc4865d45007d1bc446ed566da7
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=84f353256e170dc4865d45007d1bc446ed566da7

Changed files:
  drivers/bluetooth/btintel_pcie.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=84f353256e170dc4865d45007d1bc446ed566da7

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

The original Linux kernel CVE announcement for CVE-2026-98296 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98296

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:H/UI:N/S:U/C:N/I:N/A:L
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 7

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: 1

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).