[CVE-2026-72024][MODERATE REGULAR] mac802154: remove interfaces with RCU list deletion

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

CVE: CVE-2026-72024
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: mac802154: remove interfaces with RCU list deletion
Commit: 72ac5af9ad09662bd0ea91cb8845d490c8ef9c01
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=72ac5af9ad09662bd0ea91cb8845d490c8ef9c01
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72024
Analysis date: Sun, 16 Aug 2026 06:45:51 -0400
ActionableScore: 4
ActionableScore lower bound: 1
Actionable bucket: Borderline manual review recommended / not an Important candidate by default
Manual review required: YES

Summary:
A mac802154 bulk interface teardown race can remove an interface with `list_del()` while RCU readers still walk the interface list, allowing an asynchronous transmit completion to follow a poisoned list node and crash the kernel.

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

The original Linux kernel CVE announcement for CVE-2026-72024 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72024

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 REGULAR
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-2026-72024	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:L/I:L/A:H';CWE-362;*CWE-672;*CWE-416;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.8';DESCR 'mac802154 removes interfaces while queue wake stop and disable paths may still walk local interfaces under RCU. Using list_del can poison the list node before an asynchronous transmit completion reaches ieee802154_wake_queue(), so an RCU reader can follow an invalid list pointer and crash the kernel. For the CVSS the PR:L is used for the paranoid score because reliable triggering needs local code or a local process that can combine 802.15.4 interface teardown with transmit activity, but this may be delegated through net administration capabilities rather than full host root. The issue is not directly network reachable from packet traffic alone. Impact is at least local denial of service via kernel crash, and limited confidentiality or integrity impact is kept only in the paranoid score because this is an RCU list lifetime bug but the patch context does not show an arbitrary write primitive.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline manual review recommended / not an Important candidate by default (with actual score 3)	YES	DANGER SIMPLEFIX HARDWARE SYZBOT  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	NO	NO	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=4
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 4
* Final recommended bucket: **Borderline manual review recommended / not an Important candidate by default**::

## 2. Signal breakdown

Conservative signals:

* `+1 Real lifetime corruption`: this is an RCU list lifetime bug. RCU readers may walk `local->interfaces` while teardown removes an entry with plain `list_del()`.
* `+1 Memory corruption, weak/indirect corruption candidate`: the reader can follow a poisoned list node, but the patch does not show attacker-controlled reclaim, overwrite, callback control, or type confusion.
* `+1 Reliable kernel crash / strong DoS`: the commit explicitly describes an asynchronous transmit completion reaching `ieee802154_wake_queue()` and following a poisoned node.
* `-1 Hard or unreliable race / special timing required`: triggering requires overlap between bulk interface teardown and asynchronous transmit completion.
* `-2 Requires admin/root/CAP_NET_ADMIN in typical deployments`: bulk hardware/interface teardown is normally a privileged network-device management operation.

Paranoid additions/adjustments:

* `+1 Local low-privileged or delegated trigger concern`: in some setups, network administration may be delegated to a container root, service account, or reduced-capability process rather than full host root.
* No LPE bonus is awarded. This is a race/RCU UAF-style bug, but no controlled reclaim, write-after-free, callback dispatch, refcount takeover, or arbitrary write is shown.
* No confidentiality or integrity impact is awarded in the conservative score. Limited C/I concern is only a manual-review reason, not a demonstrated primitive.

## 3. Reachability analysis

The bug is local and control-plane oriented. A realistic trigger needs 802.15.4 interface teardown while queue wake, stop, disable, or transmit completion paths are concurrently walking `local->interfaces` under RCU. In typical deployments, removing interfaces or tearing down the hardware path requires administrative privileges such as `CAP_NET_ADMIN` or root-level device control.

Namespaces and containers may matter if a product delegates network administration to less trusted container root or service accounts. That supports the paranoid score, but it does not make the issue remotely reachable. The affected subsystem is relatively niche compared with core TCP/IP or netfilter, and exploitation depends on 802.15.4/mac802154 being present and active.

Call-site confidence: medium-high. The commit directly names the RCU readers and `ieee802154_wake_queue()`, but the full surrounding call graph is not included.

## 4. Severity interpretation

This behaves primarily like a local DoS from an RCU lifetime bug. It is not an ordinary harmless cleanup because plain `list_del()` can poison a node still visible to RCU readers, which is a real kernel memory-lifetime issue. However, the evidence supports invalid stale-list traversal and crash more strongly than privilege escalation.

Theoretical memory-safety concern exists because this is an RCU/list deletion race, but realistic exploitation evidence is limited. No attacker-controlled object reuse, arbitrary write, type confusion, or callback hijack is shown. Therefore this is best treated as borderline/manual-review Moderate, not a strong Important candidate.

## 5. One-sentence report phrase

A mac802154 bulk interface teardown race can remove an interface with `list_del()` while RCU readers still walk the interface list, allowing an asynchronous transmit completion to follow a poisoned list node and crash the kernel.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Reason: this is an RCU lifetime/list deletion race with a plausible kernel crash and possible weak memory-safety implications, even though the current patch context does not justify treating it as a proven privilege-escalation primitive.

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

Patch: mac802154: remove interfaces with RCU list deletion
Commit: 72ac5af9ad09662bd0ea91cb8845d490c8ef9c01
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=72ac5af9ad09662bd0ea91cb8845d490c8ef9c01

Commit description:

Queue wake, stop, and disable paths walk local->interfaces under RCU.
The bulk hardware teardown path removes entries with list_del(), so an
asynchronous transmit completion can follow a poisoned list node in
ieee802154_wake_queue().

Use list_del_rcu() as in the single-interface removal path. The following
unregister_netdevice() waits for in-flight RCU readers before freeing the
netdevice, so no separate grace-period wait is needed.

Fixes: 592dfbf ("mac820154: move interface unregistration into iface")
Reported-by: syzbot+36256deb69a588e9290e@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=36256deb69a588e9290e
Cc: stable@vger.kernel.org
Signed-off-by: Yousef Alhouseen <alhouseenyousef@gmail.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://patch.msgid.link/20260701164222.9094-1-alhouseenyousef@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  net/mac802154/iface.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=72ac5af9ad09662bd0ea91cb8845d490c8ef9c01

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

The original Linux kernel CVE announcement for CVE-2026-72024 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72024

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:L/I:L/A:H
  The Best / paranoid CVSS score: 5.8

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: 1
  Paranoid ActionableScore: 4

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 REGULAR

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).