[CVE-2026-98602][MODERATE REGULAR] Bluetooth: bnep: fix out-of-bounds reads on short RX/TX frames and control fallthrough [ Upstream

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

CVE: CVE-2026-98602
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: Bluetooth: bnep: fix out-of-bounds reads on short RX/TX frames and control fallthrough [ Upstream
Commit: 7af80ad2cebfe2f1879d6a39a1aaa061d9c4e1ca
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7af80ad2cebfe2f1879d6a39a1aaa061d9c4e1ca
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98602
Analysis date: Mon, 19 Oct 2026 03:11:44 -0400
ActionableScore: 3
ActionableScore lower bound: unknown
Actionable bucket: Borderline / manual review recommended
Manual review required: YES

Summary:
A Bluetooth BNEP peer can trigger out-of-bounds reads with short malformed frames, while a short local AF_PACKET TX frame can cause an out-of-bounds heap read and potential information disclosure.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-98602 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98602

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-2026-98602	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-98602 CHECK WITH IMPACT FROM ORIG NN IMPORTANT | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=2 LEGACY=MODERATE RESULT=DIFF (final Legacy and Aegis differ; FINAL: MODERATE, Aegis: MODERATE_KPANIC)	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H';CWE-125;*CWE-20;*CWE-200;Other CVSS 'AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '7.1';DESCR 'Bluetooth BNEP frame processing can read beyond the end of short RX or TX skbs because several header fields and extension lengths are consumed without complete frame length validation. A Bluetooth peer with access to an active or reachable BNEP PAN session may submit malformed control or extension frames and trigger invalid heap reads. A local process able to inject short AF_PACKET frames can also reach the TX path and potentially expose adjacent heap data. For the CVSS the PR:N value is used for the paranoid score because the RX path can be reached by a Bluetooth peer without local code execution or a user account on the target, although Bluetooth proximity and BNEP session access are required. The attack vector is AV:A rather than AV:N because Bluetooth BNEP requires adjacent wireless or PAN connectivity and is not normally reachable from the public Internet. Impact is at least disruption of BNEP processing and in the worst still defensible case includes a limited information leak and a kernel crash. No integrity impact is assigned because the demonstrated primitive is an out of bounds read rather than an out of bounds write. Automated impact decision path. The original SimpleNet classifier selected IMPORTANT. The primary LLM estimated paranoid CVSS 7.1 and the production ActionableScore returned 3 with recommendation Borderline / manual review recommended. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were ActionableScore thresholds stage IMPORTANT to MODERATE because the ActionableScore threshold rule was applied. The legacy KP specialist has no review artifact for this run. The legacy FD or DH downgrade specialist has no review artifact for this run. Exact triggered rule markers were DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 and V41_INHERITED_KPANIC_PROMOTION_BLOCKED and MANUAL_REVIEW_REQUIRED. The independent weaker Aegis shadow evaluated CVSS 3.3 and ActionableScore 2 with primitive class CLASS_C and manual review RECOMMENDED. Its independently reconciled impact was MODERATE_KPANIC. The models disagreed but the aggregation rules retained the production result. The final reported impact is MODERATE.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended (with actual score 3)	MAYBE	REMOTE WRITE OOB SIMPLEFIX LEAK NETWORK SKB LINUS  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 V41_INHERITED_KPANIC_PROMOTION_BLOCKED MANUAL_REVIEW_REQUIRED	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=3
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=NO
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=REQUIRED
AutoDowngradeAllowed=NO
RequiresHostUID0=NO
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO

1. ActionableScore

* Raw conservative score: 3
* Conservative score: 3
* Raw paranoid score: 3
* Paranoid score: 3
* No floor or cap was applied.
* Final recommended bucket: **Borderline / manual review recommended**::

2. Signal breakdown

Positive signals:

* +2 Direct network trigger. A Bluetooth peer with access to a BNEP PAN session can supply short control or extension frames to the RX parser. This is adjacent-network rather than Internet reachability.
* +1 Confidentiality plausible. The commit explicitly identifies an out-of-bounds heap read and information leak when a short AF_PACKET TX frame is interpreted as containing a complete Ethernet header.

No paranoid increase was applied because the patch establishes only reads and control fallthrough. It does not establish a write, reliable kernel panic, UAF, or stronger disclosure primitive.

Material non-awarded signals:

* No OOB write, arbitrary write, UAF, controlled reclaim, callback influence, or privilege escalation is demonstrated.
* Reliable kernel crash was not awarded. An invalid read can fault under some layouts or instrumentation, but a host-wide crash is not established.
* Integrity was not awarded because no write to kernel or packet state is shown.
* Local unprivileged trigger was not awarded for the TX path because short AF_PACKET injection normally requires CAP_NET_RAW or equivalent delegated access.
* NEW52 B5-R does not apply. There is no retry-accumulated write.
* NEW53 B3-PENDING does not apply. There is no write into shared or file-backed storage.
* V32, V33, and V34 do not apply. No attacker-controlled checksum placement or active structured-state write exists.
* B4-PENDING does not apply. No authorization guard changes from DENY to ALLOW.

3. Reachability analysis

The RX path is reachable by a Bluetooth peer that can communicate over an active or reachable BNEP PAN session. This supports HostAdminRequired=NO and RequiresHostUID0=NO for that path. Bluetooth proximity, BNEP support, and session access remain prerequisites, so this is adjacent-network exposure rather than general remote Internet exposure.

The TX information-leak path is local and uses short AF_PACKET frames. CAP_NET_RAW or equivalent delegated packet-injection access is normally relevant. The supplied evidence does not establish an ordinary unprivileged TX trigger, but that restriction does not remove the separate peer-controlled RX path.

No user-namespace or network-namespace capability is needed for the peer RX trigger, so NamespaceScopedPrivilege=NO. There is no race or timing dependency.

4. Primitive and severity interpretation

The exact primitive is a set of limited heap out-of-bounds reads caused by missing skb length validation, together with control-frame fallthrough into Ethernet-frame processing. This is not a lifetime violation and RealUAF is NO.

The strongest demonstrated non-crash consequence is the stated TX information leak. The RX path establishes attacker-controlled malformed input but does not establish that bytes read beyond the intended frame are returned to the remote peer. A crash remains plausible but unresolved rather than demonstrated.

PrimitiveClass is CLASS_C because the patch shows invalid reads and parser-state misuse without memory modification or an independently strong corruption primitive. ImportantCandidate is NO because no write, protected-state modification, authorization bypass, or escalation mechanism is present. AutoDowngradeAllowed is NO only to prevent automatic closure before the explicit adjacent-network and information-leak paths are manually confirmed. This does not classify the issue as Important.

5. One-sentence report phrase

A Bluetooth BNEP peer can trigger out-of-bounds reads with short malformed frames, while a short local AF_PACKET TX frame can cause an out-of-bounds heap read and potential information disclosure.

6. Manual review recommendation

MANUAL CHECK REQUIRED

Confirm whether the TX read is observable in transmitted BNEP data and whether malformed RX frames can cause a production-kernel fault, because these details determine the actual confidentiality and availability impact.

7. Call-site confidence

Call-site confidence: medium

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UPSTREAM PATCH SUMMARY
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Patch: Bluetooth: bnep: fix out-of-bounds reads on short RX/TX frames and control fallthrough [ Upstream
Commit: 7af80ad2cebfe2f1879d6a39a1aaa061d9c4e1ca
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7af80ad2cebfe2f1879d6a39a1aaa061d9c4e1ca

Changed files:
  net/bluetooth/bnep/core.c
  net/bluetooth/bnep/netdev.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=7af80ad2cebfe2f1879d6a39a1aaa061d9c4e1ca

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

The original Linux kernel CVE announcement for CVE-2026-98602 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98602

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:N/I:N/A:L
  The Best / paranoid CVSS vector: AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
  The Best / paranoid CVSS score: 7.1

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: 3

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).