[CVE-2026-98480][LOW] nfc: trf7970a: power down on startup RX gain failure

[CVE-2026-98480][LOW] nfc: trf7970a: power down on startup RX gain failure

[AL-KERNEL]

CVE: CVE-2026-98480
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: nfc: trf7970a: power down on startup RX gain failure
Commit: cc444e4ad43461374dd128573eccb8979d2adb4c
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=cc444e4ad43461374dd128573eccb8979d2adb4c
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98480
Analysis date: Sat, 24 Oct 2026 06:07:20 -0400
ActionableScore: 1
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
An RX-gain SPI failure during TRF7970A startup leaks a regulator-enable reference and leaves the NFC device powered.

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

The original Linux kernel CVE announcement for CVE-2026-98480 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98480

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: LOW
Manual review required: NO

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-2026-98480	LOW	https://www.kernelcve.org/list/?q=CVE-2026-98480 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT LOW AEGIS_AS=0 LEGACY=LOW RESULT=SAME (final reconciliation agrees; DECISION: both LOW)	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';*CWE-772;CWE-404;CWE-703;BEST CVSS score: '2.5';DESCR 'The bug is an error path resource leak rather than memory corruption. trf7970a_startup powers the NFC device before updating the optional RX gain setting, but an SPI read or write failure returned while leaving the startup VIN reference and enable GPIO state active. The demonstrated consequence is an unbalanced regulator enable and a device that may remain powered, with no supported UAF, OOB access, information leak, privilege escalation, or host wide crash primitive. For the CVSS the PR:L value is a conservative choice for a local actor able to initiate relevant power management operations, but reliable triggering also requires an RX gain SPI failure that is not shown to be attacker controlled. The issue is not network reachable and the practical impact is limited to device power state and availability. Automated impact decision path. The original SimpleNet classifier selected MODERATE. The primary LLM estimated paranoid CVSS 2.5 and the production ActionableScore returned 1 with recommendation Ordinary Moderate. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were CVSS and initial triage stage MODERATE to LOW because the CVSS score, vector or bug class 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_LOW_FROM_MODERATE_BASED_ON_GUESSCVSS. The independent weaker Aegis shadow evaluated CVSS 2.5 and ActionableScore 0 with primitive class CLASS_C and manual review REQUIRED. Its independently reconciled impact was LOW. The shadow agreed with the final production impact and aggregation did not change that impact. The final reported impact is LOW.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1)	MAYBE	SIMPLEFIX HARDWARE LINUS TEST  DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_GUESSCVSS	-	-	checked

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

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

1. ActionableScore

* Raw base score: 1
* Conservative score: 1; no floor or cap applied.
* Raw paranoid score: 1
* Paranoid score: 1; no additional technically supported impact.
* Final recommended bucket: **Ordinary Moderate**::

2. Signal breakdown

* +1 Concrete persistent kernel resource/reference leak: startup enables VIN and powers the device, but an RX-gain SPI error loses that additional enable reference; probe unwind releases only its separate references.
* +0 Reliable kernel crash/strong DoS: the evidence shows a device remaining powered, not a host crash or demonstrated device outage.
* No UAF, OOB read/write, shared-backing write, corrupted-state consumer, authorization bypass, confidentiality impact, integrity impact, or privilege escalation is shown.
* B5-R does not apply: there is no retry-accumulated heap OOB write.
* No privilege, race, rarity, or hardware penalty is applied because the required trigger authority and hardware prevalence are not sufficiently established.

3. Reachability analysis

The affected paths are device startup during probe and system resume. Triggering additionally requires failure of the optional RX-gain SPI register read or write. No evidence shows that a local user, NFC peer, namespace actor, or delegated service can induce that failure. Conversely, host-admin-only triggering is also not positively established, so host privilege remains unknown. No namespace capability or special timing race is involved.

4. Primitive and severity reading

The exact defect is unbalanced power-resource ownership: an error return omits `trf7970a_power_down()`, leaving enable GPIO state and a VIN regulator reference active. This is CLASS_C invalid device/power state, not memory corruption or a lifetime-invalid object use. The demonstrated consequence is excess power/resource retention. Broader device damage, host-wide availability loss, or attacker-controlled repetition is unproven. There is no Important-preserving primitive, so automatic downgrade is allowed.

5. One-sentence report phrase

An RX-gain SPI failure during TRF7970A startup leaks a regulator-enable reference and leaves the NFC device powered.

6. Manual review advice

NO MANUAL CHECK NEEDED

The patch establishes only a constrained device power-state/resource leak without attacker-controlled corruption or a security-boundary effect.

7. Call-site confidence

Call-site confidence: high

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

Patch: nfc: trf7970a: power down on startup RX gain failure
Commit: cc444e4ad43461374dd128573eccb8979d2adb4c
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=cc444e4ad43461374dd128573eccb8979d2adb4c

Commit description:

trf7970a_startup() powers up the device before applying the optional RX
gain reduction. If the register read or write fails, it returns without
undoing that power-up. Probe's unwind only drops the separate regulator
references acquired by probe, leaving the additional VIN enable from
startup unbalanced. The system resume caller also has no power-down on
this error.

Call trf7970a_power_down() before returning the RX gain error to deassert
the enable GPIOs, release the startup VIN reference and restore the
powered-off state. Runtime PM has not been enabled yet, so the full
shutdown helper is not appropriate here. Preserve the original SPI error.

This issue was identified during our ongoing static-analysis research while
reviewing kernel code.

Fixes: 5d69351 ("NFC: trf7970a: Create device-tree parameter for RX gain reduction")
Cc: stable@vger.kernel.org
Assisted-by: OpenAI:GPT-5.6
Co-developed-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Myeonghun Pak <mhun512@gmail.com>
Reviewed-by: Paul Geurts <paul.geurts@prodrive-technologies.com>
Link: https://patch.msgid.link/20260913042625.31296-1-mhun512@gmail.com
Signed-off-by: David Heidelberg <david@ixit.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/nfc/trf7970a.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=cc444e4ad43461374dd128573eccb8979d2adb4c

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

The original Linux kernel CVE announcement for CVE-2026-98480 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98480

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: Not available
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
  The Best / paranoid CVSS score: 2.5

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: 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: LOW
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): LOW

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).