[CVE-2026-74554][MODERATE 7.0] wifi: ath12k: fix out-of-bounds clear_bit in ath12k_mac_dp_peer_cleanup() [ Upstream

[CVE-2026-74554][MODERATE 7.0] wifi: ath12k: fix out-of-bounds clear_bit in ath12k_mac_dp_peer_cleanup() [ Upstream

[AL-KERNEL]

CVE: CVE-2026-74554
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: wifi: ath12k: fix out-of-bounds clear_bit in ath12k_mac_dp_peer_cleanup() [ Upstream
Commit: 234b5cb81e6fcc1e3b31b13deff66130be55f36e
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=234b5cb81e6fcc1e3b31b13deff66130be55f36e
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74554
Analysis date: Sat, 15 Aug 2026 13:11:13 -0400
ActionableScore: 7
ActionableScore lower bound: 5
Actionable bucket: Strong Important candidate / Actionable Moderate at minimum
Manual review required: YES

Summary:
An out of bounds clear_bit in ath12k MLO peer cleanup can corrupt kernel memory adjacent to free_ml_peer_id_map when externally influenced WiFi peer teardown reaches the affected path, making this at least a DoS risk and a manual review candidate for possible broader memory corruption impact.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-74554 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74554

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-2026-74554	MODERATE	CHECK WITH IMPACT FROM ORIG NN IMPORTANT	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H';*CWE-787;CWE-119;CWE-122;*CWE-787;Other CVSS 'AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '7.5';DESCR 'An out of bounds write in the ath12k MLO peer cleanup path occurs because clear_bit is called with dp_peer peer_id even though an MLO peer_id includes the ATH12K_PEER_ML_ID_VALID bit. This makes the bit index at least 0x2000 while free_ml_peer_id_map only covers 256 bits, so memory adjacent to the bitmap can be corrupted during peer cleanup. For the CVSS the PR:N is used because a nearby WiFi attacker may be able to influence MLO peer creation and teardown without a local account on the victim, assuming affected ath12k hardware and an exposed MLO capable wireless role. The issue is not Internet reachable but is adjacent network reachable over WiFi. Impact is at least denial of service and memory corruption. In the paranoid interpretation it may allow confidentiality and integrity impact or privilege escalation because the primitive is an out of bounds kernel memory bit clear rather than a pure NULL dereference or resource leak.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 7)  SKIP CVE-2026-74554 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: ee16dcf573d5e3283fda601dd4bca6bc52251017 YES  NO NO unknown 	MAYBE	REMOTE WRITE OOB SIMPLEFIX NETWORK LINUS KPANIC  DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFKP	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=7
ActionableScoreLower=5

## 1. ActionableScore

* Conservative score: **5**
* Paranoid score: **7**
* Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**::

## 2. Signal breakdown

Conservative signals:

* Firmware-mediated external influence: **+1**. Peer lifecycle can be influenced externally over WiFi, but the exact host-side cleanup path depends on ath12k firmware, MLO state, and device role.
* Constrained kernel memory corruption: **+1**. `clear_bit()` writes out of bounds, but the payload is a single bit clear and the target is a fixed offset relative to `free_ml_peer_id_map`.
* Reliable kernel crash / strong DoS: **+1**. The commit explicitly says adjacent memory is corrupted and ML peer IDs may be leaked until allocation fails.
* Integrity impact plausible: **+1**. The bug performs an unintended write into kernel memory.
* Privileged kernel/device-management corruption path: **+1**. The corruption occurs inside trusted WiFi driver peer cleanup state.
* Corruption primitive constrained or metadata-only: **-1**. No arbitrary payload or attacker-selected kernel target is shown.
* Hardware/configuration dependent: **-1**. Practical exposure requires affected ath12k hardware and an MLO-capable path.

Paranoid additional interpretation:

* Adjacent network reachable: **+2 instead of +1**. A nearby WiFi attacker may be able to influence MLO peer creation and teardown without a local account.
* Memory corruption, strong primitive: **+2 instead of +1**. The primitive is an actual OOB kernel write, even if limited to clearing one bit.
* Weak LPE concern: **+1**. Privilege escalation is not demonstrated, but kernel memory corruption adjacent to driver state is enough to require manual review.

Call-site confidence: **high**. The changed call site and the bad index source are visible in the patch.

## 3. Reachability analysis

A local user account is not required if the vulnerable MLO peer cleanup can be reached through WiFi peer creation and deletion driven by a nearby station or AP. This is not Internet-reachable in the normal IP sense. It is adjacent-network reachable over WiFi under affected ath12k hardware and MLO-capable deployment conditions.

Namespaces and containers do not materially reduce the attacker requirement for the adjacent WiFi case, because the trigger is outside the local userspace privilege model. If the path is only reachable through administrator-controlled wireless configuration in a specific product, the conservative score is more appropriate.

## 4. Severity interpretation

This is not an ordinary Moderate bookkeeping bug. The patch fixes a concrete OOB write in kernel memory caused by using `dp_peer->peer_id` with `ATH12K_PEER_ML_ID_VALID` still set as a bitmap index.

Realistic exploitation evidence is limited because the write is constrained to clearing a bit at a derived offset and depends on ath12k MLO peer lifecycle behavior. However, the bug class is kernel memory corruption in a remotely influenced WiFi driver path, so it should not be auto-closed as a low-risk DoS-only issue.

## 5. One-sentence report phrase

An out of bounds clear_bit in ath12k MLO peer cleanup can corrupt kernel memory adjacent to free_ml_peer_id_map when externally influenced WiFi peer teardown reaches the affected path, making this at least a DoS risk and a manual review candidate for possible broader memory corruption impact.

## 6. Manual review recommendation

**MANUAL CHECK REQUIRED**

Reason: the patch fixes a real OOB kernel write in a WiFi driver path with possible adjacent-network influence. Even though the primitive is constrained, this class should be manually reviewed for object layout, adjacent fields, crash reliability, and whether MLO peer lifecycle can be triggered by an untrusted nearby WiFi peer.

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

Patch: wifi: ath12k: fix out-of-bounds clear_bit in ath12k_mac_dp_peer_cleanup() [ Upstream
Commit: 234b5cb81e6fcc1e3b31b13deff66130be55f36e
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=234b5cb81e6fcc1e3b31b13deff66130be55f36e

Changed files:
  drivers/net/wireless/ath/ath12k/mac.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=234b5cb81e6fcc1e3b31b13deff66130be55f36e

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

The original Linux kernel CVE announcement for CVE-2026-74554 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74554

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:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H
  The Best / paranoid CVSS vector: AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 7.5

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: 5
  Paranoid ActionableScore: 7

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