[CVE-2026-53339][LOW] i2c: qcom-cci: Fix NULL pointer dereference in cci_remove()

[CVE-2026-53339][LOW] i2c: qcom-cci: Fix NULL pointer dereference in cci_remove()

[AL-KERNEL]

CVE: CVE-2026-53339
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: i2c: qcom-cci: Fix NULL pointer dereference in cci_remove()
Commit: e8669d12da0ade52adfe0abe96cd99e708abc9bd
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e8669d12da0ade52adfe0abe96cd99e708abc9bd
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53339
Analysis date: Wed, 01 Jul 2026 10:24:21 -0400
ActionableScore: 1
ActionableScore lower bound: 0
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
A NULL pointer dereference in the qcom-cci remove path can crash the kernel when an affected Qualcomm CCI device with only one initialized I2C master is unbound or the module is removed, requiring local driver-management privileges and causing DoS only.

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

The original Linux kernel CVE announcement for CVE-2026-53339 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53339

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-2026-53339	LOW	CHECK	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H';**CWE-476;CWE-754;CWE-703;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.5';DESCR 'A NULL-pointer dereference in the qcom-cci I2C driver remove path can occur because cci_remove calls cci_halt for both CCI masters even when only one master was initialized by the platform. On boards with a single enabled master, driver unbind or module removal can reach wait_for_completion_timeout with an uninitialized completion state and crash the kernel. For the CVSS the PR:L paranoid interpretation applies only if a less privileged service account or reduced capability root can trigger driver unbind or module removal through delegated control. In the typical deployment PR:H is more realistic because removing a kernel module or unbinding the platform driver requires administrative privileges. The issue is not network reachable and requires local control of the affected driver lifecycle. Impact is denial of service via kernel crash only.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 1)	YES	OOB NULLPTR USB HARDWARE LINUS  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	YES	NO	checked

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

ActionableScore=1
ActionableScoreLower=0

## 1. ActionableScore

* Conservative score: 0
* Paranoid score: 1
* Final recommended bucket: **Ordinary Moderate / Low-like**::

## 2. Signal breakdown

Conservative signals:

* Reliable kernel crash / strong DoS: +1. The commit shows a NULL pointer dereference during `rmmod` or driver unbind.
* Requires admin/root/CAP_SYS_MODULE or equivalent in typical deployments: -2. Module removal or platform driver unbind normally requires administrative control.
* Rare AND difficult-to-reach subsystem/configuration: -1. This affects Qualcomm CCI hardware and only boards where one of two I2C masters is not initialized.
* Score is clamped to 0.

Paranoid signals:

* Reliable kernel crash / strong DoS: +1. The crash is deterministic once the affected hardware/configuration and removal path are present.
* No full admin penalty in the paranoid interpretation if driver unbind is delegated to a reduced-capability service account or container root with device-management access.
* No memory-corruption, UAF, double-free, OOB write, type confusion, callback overwrite, or LPE primitive is shown.

## 3. Reachability analysis

The bug is triggered locally through the driver lifecycle path, specifically module removal or device unbind. It is not network reachable and cannot be triggered by normal I2C traffic from a remote attacker. In typical deployments, the required action needs host administrative privileges, such as root or CAP_SYS_MODULE-like control. Namespaces or containers usually do not expose platform-driver unbind or module removal, but a reduced-privilege service with delegated device-management control could make the paranoid PR:L-style interpretation relevant. The vulnerable path is hardware and board dependent, requiring Qualcomm CCI with only one initialized master.

Call-site confidence: high. The patch directly shows `cci_halt()` moved inside the initialized-master check in `cci_remove()`.

## 4. Severity interpretation

This behaves like a local privileged DoS, not an Important-class vulnerability. The theoretical impact is a kernel crash via NULL pointer dereference, but the patch does not show a reclaimable UAF, writable stale object, attacker-controlled overwrite, or any plausible privilege-escalation primitive. The realistic exploitation condition is local control over driver removal on affected Qualcomm platforms, which makes this ordinary Moderate or Low-like for practical triage.

## 5. One-sentence report phrase

A NULL pointer dereference in the qcom-cci remove path can crash the kernel when an affected Qualcomm CCI device with only one initialized I2C master is unbound or the module is removed, requiring local driver-management privileges and causing DoS only.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED.

This is a local driver teardown NULL dereference with administrative trigger requirements and no evidence of memory corruption beyond the immediate crash.

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

Patch: i2c: qcom-cci: Fix NULL pointer dereference in cci_remove()
Commit: e8669d12da0ade52adfe0abe96cd99e708abc9bd
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e8669d12da0ade52adfe0abe96cd99e708abc9bd

Commit description:

On all modern platforms Qualcomm CCI controller provides two I2C masters,
and on particular boards only one I2C master may be initialized, and in
such cases the device unbinding or driver removal causes a NULL pointer
dereference, because cci_halt() is called for all two I2C masters, but
a completion is initialized only for the single enabled master:

    % rmmod i2c-qcom-cci
    Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
    <snip>
    Call trace:
    __wait_for_common+0x194/0x1a8 (P)
    wait_for_completion_timeout+0x20/0x2c
    cci_remove+0xc4/0x138 [i2c_qcom_cci]
    platform_remove+0x20/0x30
    device_remove+0x4c/0x80
    device_release_driver_internal+0x1c8/0x224
    driver_detach+0x50/0x98
    bus_remove_driver+0x6c/0xbc
    driver_unregister+0x30/0x60
    platform_driver_unregister+0x14/0x20
    qcom_cci_driver_exit+0x18/0x1008 [i2c_qcom_cci]
    ....

Fixes: e517526 ("i2c: Add Qualcomm CCI I2C driver")
Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
Cc: <stable@vger.kernel.org> # v5.8+
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20260515234121.1607425-2-vladimir.zapolskiy@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/i2c/busses/i2c-qcom-cci.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=e8669d12da0ade52adfe0abe96cd99e708abc9bd

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

The original Linux kernel CVE announcement for CVE-2026-53339 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53339

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:L/PR:H/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 5.5

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: 0
  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).