[CVE-2026-74519][MODERATE 7.0] pinctrl: devicetree: don't free uninitialized dev_name on error path

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

CVE: CVE-2026-74519
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: pinctrl: devicetree: don't free uninitialized dev_name on error path
Commit: 929f6396baade89999ec8a1281232c101cbc727d
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=929f6396baade89999ec8a1281232c101cbc727d
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74519
Analysis date: Sat, 15 Aug 2026 14:20:06 -0400
ActionableScore: 5
ActionableScore lower bound: 3
Actionable bucket: Actionable Moderate at minimum
Manual review required: YES

Summary:
A pinctrl DeviceTree cleanup error can pass uninitialized `dev_name` pointers to `kfree_const()` after partial allocation failure, causing a KASAN-confirmed double-free and local kernel crash, with theoretical but unproven privilege escalation risk.

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

The original Linux kernel CVE announcement for CVE-2026-74519 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74519

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.

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AL-KERNEL CLASSIFICATION RESULT
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CVE-2026-74519	MODERATE	CHECK WITH IMPACT FROM ORIG NN MODERATE	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-824;CWE-415;CWE-665;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7';DESCR 'A memory corruption bug in the pinctrl DeviceTree mapping path can occur when dt_remember_or_free_map() handles a partial allocation failure. If kstrdup_const() fails after only some map entries were initialized, dt_free_map() may pass uninitialized dev_name values from untouched kmalloc backed entries to kfree_const(), resulting in an invalid free or double-free. The observed failure was reproduced with failslab injection during binding of a pinctrl consuming device and was reported by KASAN as a double-free. For the CVSS the PR:L is used in the paranoid score because a local user may be able to influence memory pressure or device binding in some delegated environments, although typical direct control over pinctrl binding is administrative. The issue is not network reachable. Impact is at least a local denial of service via kernel crash and in worst case may allow confidentiality or integrity impact due to kernel heap memory corruption and should be reviewed manually.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 4)	YES	DANGER INIT ERRORPATH UAF HARDWARE  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	NO	NO	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=5
ActionableScoreLower=3

## 1. ActionableScore

* Conservative score: 3
* Paranoid score: 5
* Final recommended bucket: **Actionable Moderate at minimum**

## 2. Signal breakdown

Conservative signals:

* Memory corruption, strong corruption primitive: +2
  The patch prevents an uninitialized `dev_name` pointer from being passed to `kfree_const()`, and KASAN reports a real double-free in `dt_free_map()`.

* Real lifetime corruption: +1
  This is a cleanup/lifetime bug in a partial initialization error path where uninitialized entries are freed as if they were valid initialized objects.

* Reliable kernel crash / strong DoS: +1
  The reported KASAN double-free can crash the kernel when the allocation failure path is reached.

* Requires admin/root/CAP_* in typical deployments: -2
  Reliable triggering normally requires device binding, devicetree/pinctrl setup, or fault-injection style conditions, which are typically administrator-controlled.

* Hard or special trigger condition: -1
  The reproducer depends on `failslab` during binding of a pinctrl-consuming device, so normal unprivileged reachability is weak.

Paranoid additions:

* Weak LPE concern: +1
  Double-free in kernel heap cleanup is a memory corruption class that can sometimes be exploitable, but the patch does not show attacker-controlled reclaim, payload control, or callback control.

* Confidentiality impact plausible: +1
  Only for paranoid scoring, because kernel heap corruption may theoretically affect sensitive kernel data.

* Integrity impact plausible: +1
  Only for paranoid scoring, because a double-free can theoretically become more than DoS if object reuse is controllable.

Paranoid score is capped at 5 because the bug is real memory corruption, but the trigger is specialized and no practical reclaim or overwrite primitive is demonstrated.

## 3. Reachability analysis

The bug is local, not network reachable. It occurs in the pinctrl DeviceTree mapping path when `dt_remember_or_free_map()` partially initializes map entries and then unwinds after `kstrdup_const()` failure. Some drivers allocate the map with `kmalloc()` and rely on the core to initialize `dev_name`, so untouched entries can contain stale heap data.

Typical triggering requires administrator-level control over device binding or a fault-injection environment. A normal unprivileged user usually cannot directly cause pinctrl DeviceTree binding paths to execute with controlled allocation failure timing. Containers and namespaces generally do not expose this path unless the environment delegates device management or fault-injection controls, which is uncommon.

## 4. Severity interpretation

This is not an ordinary low-risk cleanup bug because the observed failure is a KASAN-confirmed double-free. However, it is also not a strong Important candidate by default because the trigger path is an error path requiring allocation failure during device binding, and the patch does not demonstrate attacker-controlled reclaim, object replacement, arbitrary write, or a practical LPE chain.

Realistic impact is local kernel crash / DoS under special conditions. Theoretical impact includes possible local privilege escalation due to kernel heap double-free, but that requires further manual analysis.

## 5. One-sentence report phrase

A pinctrl DeviceTree cleanup error can pass uninitialized `dev_name` pointers to `kfree_const()` after partial allocation failure, causing a KASAN-confirmed double-free and local kernel crash, with theoretical but unproven privilege escalation risk.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Reason: the issue is a real double-free in kernel heap cleanup code. Even though practical triggering appears privileged and fault-condition dependent, memory corruption bugs of this class should not be auto-closed without manual review.

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

Patch: pinctrl: devicetree: don't free uninitialized dev_name on error path
Commit: 929f6396baade89999ec8a1281232c101cbc727d
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=929f6396baade89999ec8a1281232c101cbc727d

Commit description:

dt_remember_or_free_map() duplicates dev_name for each map entry. If
kstrdup_const() fails, dt_free_map() frees dev_name in all num_maps
entries, including entries that have not been initialized.

Some pinctrl drivers, including pinctrl-imx, allocate the map with
kmalloc() and leave dev_name for the core to initialize. The untouched
entries therefore contain uninitialized data which is passed to
kfree_const().

Reproduced on qemu's mcimx6ul-evk (pinctrl-imx) with failslab injection
while binding the pinctrl-consuming device, under KASAN:

  BUG: KASAN: double-free in dt_free_map+0x34/0xa4
  Free of addr c425a900 by task init/1
   kfree from dt_free_map+0x34/0xa4
   dt_free_map from dt_remember_or_free_map+0x184/0x198
   dt_remember_or_free_map from pinctrl_dt_to_map+0x33c/0x4c8
   pinctrl_dt_to_map from create_pinctrl+0x9c/0x5c0

Initialize all dev_name fields to NULL before duplicating the device
name, making the full-map cleanup safe after a partial failure.

Fixes: be4c60b ("pinctrl: devicetree: Avoid taking direct reference to device name string")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-fable-5
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Signed-off-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/pinctrl/devicetree.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=929f6396baade89999ec8a1281232c101cbc727d

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

The original Linux kernel CVE announcement for CVE-2026-74519 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74519

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: 3
  Paranoid ActionableScore: 5

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 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 alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).