[CVE-2026-53093][LOW] wifi: brcmfmac: Fix error pointer dereference [ Upstream

[CVE-2026-53093][LOW] wifi: brcmfmac: Fix error pointer dereference [ Upstream

[AL-KERNEL]

CVE: CVE-2026-53093
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: wifi: brcmfmac: Fix error pointer dereference [ Upstream
Commit: a3b45090a91e2f0b9715870d8f8d9ca2fdfbc1af
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a3b45090a91e2f0b9715870d8f8d9ca2fdfbc1af
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53093
Analysis date: Fri, 26 Jun 2026 14:43:53 -0400
ActionableScore: 1
ActionableScore lower bound: 0
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
An unchecked ERR_PTR return from brcmf_chip_add_core() in brcmfmac chip recognition can be dereferenced during driver initialization, causing a local driver probe crash, but it is not network reachable and does not show a privilege escalation primitive.

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

The original Linux kernel CVE announcement for CVE-2026-53093 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53093

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-2026-53093	LOW	CHECK	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:H';**CWE-476;CWE-252;CWE-754;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '4.7';DESCR 'An ERR_PTR dereference in brcmfmac chip recognition can occur because brcmf_chip_add_core() may fail and return an error pointer that is later passed to brcmf_chip_sb_corerev(). This is reached during Broadcom WiFi chip probe or driver initialization, not through normal WiFi packet processing. For the CVSS the PR:L is used only for the paranoid interpretation where a local user or delegated service can indirectly trigger device reprobe or driver recovery operations. The realistic impact is denial of service through a kernel crash during driver initialization. There is no direct network reachability and no clear primitive for information disclosure or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 1)	YES	REMOTE SIMPLEFIX NETWORK  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	NO	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

Triggered or considered signals:

* Weak corruption (+0): this is an ERR_PTR dereference / invalid pointer dereference, not UAF, double free, OOB write, type confusion, refcount takeover, or attacker-controlled overwrite.
* Reliable kernel crash / strong DoS (+1, paranoid only): if brcmf_chip_add_core() returns ERR_PTR during chip recognition, the old code may dereference it and crash during driver probe or initialization.
* Requires admin/root/device-management control (-2, conservative): reliable triggering normally requires driver load, reprobe, device bind/unbind, or a failing hardware/resource condition.
* Rare or hardware-specific path (-1, conservative context): this affects Broadcom brcmfmac chip-recognition paths and is not a broad default kernel interface reachable on all systems.

Not counted:

* Remote reachable: no. This is not reachable through WiFi packet processing.
* Firmware-mediated external influence: not counted for the main score. The patch does not show a firmware-controlled parsing primitive.
* Generic memory corruption: no. ERR_PTR dereference is not enough to claim memory corruption.
* Privilege escalation plausible: no. There is no reclaim, overwrite, callback, type confusion, or lifetime primitive.
* Confidentiality or integrity impact: no supported primitive.

## 3. Reachability analysis

The affected path is brcmfmac chip recognition during driver probe or initialization. A normal remote WiFi peer should not be able to reach this code through packet traffic. In typical deployments, triggering requires local administrative control over driver or device lifecycle, such as module loading, device reprobe, or bind/unbind, or it depends on unusual hardware/resource failure during initialization.

Namespaces and containers do not normally make this reachable to an unprivileged user. A reduced-privilege service with delegated device-management access could make the paranoid interpretation slightly higher, but this still remains a local DoS-style issue.

## 4. Severity interpretation

This behaves like an ordinary Moderate / Low-like kernel robustness bug rather than an Important-class vulnerability. The theoretical failure mode is a kernel crash from an invalid ERR_PTR dereference. The realistic exploitation evidence supports DoS during probe or initialization only. There is no demonstrated memory corruption primitive, no network reachability, no information disclosure, and no plausible privilege escalation path from the patch context.

## 5. One-sentence report phrase

An unchecked ERR_PTR return from brcmf_chip_add_core() in brcmfmac chip recognition can be dereferenced during driver initialization, causing a local driver probe crash, but it is not network reachable and does not show a privilege escalation primitive.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

Reason: the issue is an invalid pointer dereference in a hardware-specific driver initialization path, with no supported UAF, OOB write, object lifetime abuse, information disclosure, or privilege escalation primitive.

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

Patch: wifi: brcmfmac: Fix error pointer dereference [ Upstream
Commit: a3b45090a91e2f0b9715870d8f8d9ca2fdfbc1af
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a3b45090a91e2f0b9715870d8f8d9ca2fdfbc1af

Changed files:
  drivers/net/wireless/broadcom/brcm80211/brcmfmac/chip.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=a3b45090a91e2f0b9715870d8f8d9ca2fdfbc1af

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

The original Linux kernel CVE announcement for CVE-2026-53093 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53093

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:N/I:N/A:H
  The Best / paranoid CVSS score: 4.7

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: 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).