* [CVE-2026-98666][MODERATE 7.0] iio: gyro: adis16136: fix unprotected debugfs reads
@ 2026-10-24 11:55 21% AL-KERNEL
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From: AL-KERNEL @ 2026-10-24 11:55 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-98666
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: iio: gyro: adis16136: fix unprotected debugfs reads
Commit: d5b0b62e26d7d30e0e16e2d695f2161f7e92a5a5
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d5b0b62e26d7d30e0e16e2d695f2161f7e92a5a5
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98666
Analysis date: Sat, 24 Oct 2026 07:55:15 -0400
ActionableScore: 4
ActionableScore lower bound: unknown
Actionable bucket: Borderline / manual review recommended
Manual review required: YES
Summary:
A debugfs read racing ADIS16136 unbind can dereference freed IIO private state and plausibly crash the kernel.
======================================================================
ABOUT THIS REPORT
======================================================================
The original Linux kernel CVE announcement for CVE-2026-98666 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98666
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-2026-98666 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-98666 CHECK WITH IMPACT FROM ORIG NN LOW | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=4 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:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H';*CWE-416;CWE-362;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7';DESCR 'A race exists between reading the adis16136 serial_number debugfs file and device unbind. The unsafe debugfs file operations do not acquire debugfs lifetime protection, so debugfs_remove_recursive can return and the iio_dev can be freed while the read callback is still using its private data. This creates a concrete use after free dereference with a likely kernel crash and a less certain memory corruption risk if the freed allocation is reused. For the CVSS the PR:L paranoid choice reflects deployments where debugfs access or device management is delegated to a container root or a restricted service account. Reliable triggering requires winning the read versus unbind race, so AC:H is appropriate. Automated impact decision path. The original SimpleNet classifier selected LOW. The primary LLM estimated paranoid CVSS 7 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 LOW to MODERATE_KPANIC because the ActionableScore 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_FROM_LOW_BASED_ON_GUESSCVSS_AND_ACTIONABLESCOREHIGHER4 and DECREASED_TO_MODERATEREG_BASED_ON_FALSEPOSCHECKOFKP and V39_AEGIS_ONE_STEP_UP and MANUAL_REVIEW_REQUIRED. The independent weaker Aegis shadow evaluated CVSS 2.7 and ActionableScore 4 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 WARNONLY SIMPLEFIX DEBUGFS INCREASED_TO_MODERATE7_FROM_LOW_BASED_ON_GUESSCVSS_AND_ACTIONABLESCOREHIGHER4 DECREASED_TO_MODERATEREG_BASED_ON_FALSEPOSCHECKOFKP KPANIC V39_AEGIS_ONE_STEP_UP MANUAL_REVIEW_REQUIRED - - checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=4
PrimitiveClass=CLASS_B
RealUAF=YES
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
RequiresHostUID0=UNKNOWN
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO
1. ActionableScore
* Raw base score: 2.
* Conservative score: 4. Real-UAF floor 4 applied: 2 -> 4.
* Raw paranoid score: 2.
* Paranoid score: 4. Real-UAF floor 4 applied: 2 -> 4.
* Final recommended bucket: **Borderline / manual review recommended**::
2. Signal breakdown
* +2 — Concrete UAF: `debugfs_create_file_unsafe()` does not acquire debugfs lifetime protection, allowing unbind to free `iio_dev` while the serial-number read still uses its private data.
* +1 — Plausible kernel crash from dereferencing freed driver state.
* -1 — A concurrent read must overlap the one-time device-unbind teardown; supplied evidence characterizes this as an AC:H race.
* Floor 4 — The stale reference is genuinely consumed and is not clearly just a fixed asynchronous buffer.
* No controlled reclaim, attacker-shaped replacement, directed write, callback control, disclosure, or authorization bypass is shown.
* No extra availability point: it would duplicate the same crash.
* Theoretical allocator reuse does not establish integrity impact or justify a paranoid bonus.
3. Reachability analysis
The serial-number file is debugfs mode `0400`, and the competing operation is device unbind. The supplied material does not establish whether one below-host-admin principal can both read the file and induce unbind. Delegation to a container or service is only a hypothetical deployment, not proven reachability. Namespace-scoped capability checks are not shown. The affected physical SPI/IIO device must exist, but the evidence does not justify a rare-hardware penalty.
4. Primitive and severity reading
This is an active driver-object lifetime UAF, not a repeated-release/refcount bug. Removal can free the `iio_dev` before an in-progress debugfs callback finishes using `iio_priv()` data. The shown effect is stale structured-state access with plausible Oops/crash. Non-crash exploitation through reclaimed contents remains speculative, so this is constrained CLASS_B rather than CLASS_A. ImportantCandidate is NO and auto-downgrade remains allowed because no material reuse or boundary-crossing primitive is demonstrated.
5. One-sentence report phrase
A debugfs read racing ADIS16136 unbind can dereference freed IIO private state and plausibly crash the kernel.
6. Manual review advice
MANUAL CHECK RECOMMENDED
Confirm debugfs/unbind privilege delegation and whether the read callback performs deeper operations after reclamation.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: iio: gyro: adis16136: fix unprotected debugfs reads
Commit: d5b0b62e26d7d30e0e16e2d695f2161f7e92a5a5
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d5b0b62e26d7d30e0e16e2d695f2161f7e92a5a5
Commit description:
The serial_number file operations are open coded and never call
debugfs_file_get(), which debugfs_create_file_unsafe() requires.
debugfs_remove_recursive() therefore does not wait for a read in
progress, and unbind frees the iio_dev underneath it.
Use debugfs_create_file() instead.
Fixes: 9aaea09 ("gyro:adis16136: fix debugfs_simple_attr.cocci warnings")
Signed-off-by: Arka Mondal <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Cc: [email protected]
Signed-off-by: Jonathan Cameron <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Changed files:
drivers/iio/gyro/adis16136.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=d5b0b62e26d7d30e0e16e2d695f2161f7e92a5a5
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-98666 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98666
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:H
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: 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 [email protected] (and both
send reply to CVE record itself too and see "reply" button below for howto reply).
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