* [CVE-2026-98331][MODERATE REGULAR] wifi: mac80211: unlist vifs when their netdev is unregistered [ Upstream
@ 2026-10-10 9:22 21% AL-KERNEL
0 siblings, 0 replies; 1+ results
From: AL-KERNEL @ 2026-10-10 9:22 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-98331
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: wifi: mac80211: unlist vifs when their netdev is unregistered [ Upstream
Commit: a22c02863439993095acd0c3db97fa53cd515f4f
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a22c02863439993095acd0c3db97fa53cd515f4f
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98331
Analysis date: Sat, 10 Oct 2026 05:22:49 -0400
ActionableScore: 2
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO
Summary:
No one-sentence report phrase was found.
======================================================================
ABOUT THIS REPORT
======================================================================
The original Linux kernel CVE announcement for CVE-2026-98331 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98331
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: NO
A detailed explanation of the methodology and priority rules is included
at the end of this message.
======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================
CVE-2026-98331 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-98331 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=1 LEGACY=MODERATE RESULT=DIFF (independent Legacy and Aegis differ; FINAL: MODERATE, Aegis: MODERATE_KPANIC) 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-672;*CWE-416;*CWE-664;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7';DESCR 'A mac80211 virtual interface can remain linked in local interfaces after its netdev has been unregistered through the network namespace teardown path rather than ieee80211_if_remove. A later mac80211 hardware cleanup can traverse this inconsistent entry and reach a BUG in wiphy_to_rdev, causing a local kernel crash and denial of service. The stale list entry may also outlive the associated netdev private object, making this a potential use after free candidate that requires manual source and lifetime analysis. For the CVSS the PR:L value is used because a reduced capability process with delegated network namespace or network device control may be sufficient, while full host root is not necessarily required. AV:L applies because no direct trigger through received WiFi traffic is demonstrated. AC:H applies because the vulnerable path depends on network namespace destruction combined with failure to move the wiphy, including an allocation failure. Impact is at least a local denial of service via kernel crash and in the worst case may allow confidentiality or integrity impact due to a stale object access.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2) MAYBE REMOTE DANGER INIT DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 - - checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=2
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
RequiresHostUID0=UNKNOWN
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO
1. ActionableScore
* Raw conservative score: 2
* Conservative score: 2
* Raw paranoid score: 2
* Paranoid score: 2
* No floor or cap was applied.
* Final recommended bucket: **Ordinary Moderate**::
2. Signal breakdown
* +1 Weak or indirect invalid-state primitive. An unregistered mac80211 interface remains reachable through `local->interfaces`, so later cleanup treats a nonexistent interface as active.
* +1 Reliable kernel crash or strong DoS. The supplied trace demonstrates a kernel `BUG` in `wiphy_to_rdev()` during subsequent hardware cleanup.
* No additional Availability point. It would double-count the same kernel crash.
* No UAF points. Netdev unregistration and stale list membership are established, but the supplied code does not establish that `sdata` storage is freed before the later traversal.
* No structured stale-object leverage. No post-free replacement, controlled reclaim, callback consumption, refcount mutation, or attacker-shaped reused object is demonstrated.
* No local-unprivileged bonus. Complete below-host-admin reachability is unresolved.
* No privilege penalty. Host-admin-equivalent privilege is also not positively established.
* No race penalty. The failure is an ordered teardown and allocation-failure sequence, not a demonstrated narrow race.
* No remote or networking-data-path bonus. Received WiFi traffic does not directly reach the vulnerable operation.
* No B5-R signal. There is no heap OOB write or retry-accumulated offset.
* No B3-PENDING signal. There is no shared-backing write.
* No B4-PENDING signal. No authorization decision changes from DENY to ALLOW.
Repeated-release checks:
* First lifetime-ending release: not established.
* Exact reference surviving such a release: not established.
* Second lifetime or refcount mutation: not present.
* Concrete repeated release or refcount +1: not awarded.
* Paranoid repeated-refcount +1: not awarded.
* FLOOR 5: not applicable.
3. Reachability analysis
The failure requires a wiphy associated with a network namespace, destruction of that namespace, failure to move the wiphy back to the initial namespace, and later mac80211 hardware cleanup. The supplied evidence does not establish who can perform the complete setup or whether control over the relevant wiphy requires host network administration.
The presence of a network namespace does not prove that all required operations are available through attacker-created user and network namespaces. Therefore both host-admin and namespace-scoped privilege requirements remain unknown. A prior device or mac80211_hwsim setup may be necessary, but the evidence does not resolve who creates or controls it.
The allocation failure is a material environmental prerequisite. Attacker-controlled memory pressure or reliable repetition of this exact branch is not demonstrated. There is no special physical-hardware penalty because the trace uses mac80211_hwsim and the bug is in generic mac80211 lifecycle handling.
4. Primitive and severity interpretation
The exact established primitive is stale list membership: `local->interfaces` retains an interface after its netdev has been unregistered through a path that bypasses `ieee80211_if_remove()`. Later cleanup consumes that logically invalid interface and reaches a kernel `BUG`.
This is an invalid-state cleanup path and therefore CLASS_C on the supplied evidence. It is not a confirmed post-lifetime dereference because the lifetime and freeing point of the containing `sdata` allocation are not shown. The fix is lifetime-relevant because it removes the entry in `ndo_uninit`, but that alone does not prove a real UAF.
The demonstrated consequence is local kernel denial of service. A UAF, controlled reclaim, arbitrary read or write, confidentiality loss, integrity violation, and privilege escalation remain speculative. There is no useful primitive established after excluding the crash.
ImportantCandidate is NO because only crash-producing inconsistent cleanup state is demonstrated. AutoDowngradeAllowed is YES because no unresolved corruption, repeated lifetime mutation, authorization bypass, or ownership primitive is established. Manual review remains recommended to verify the netdev and `sdata` freeing sequence before conclusively excluding a post-unregister UAF.
5. One-sentence report phrase
A mac80211 interface may remain on the interface list after external netdev unregistration, causing later hardware cleanup to process invalid state and trigger a kernel BUG and local denial of service.
6. Manual review recommendation
MANUAL CHECK RECOMMENDED
Verify whether the affected `ieee80211_sub_if_data` allocation can be freed before `ieee80211_remove_interfaces()` traverses the stale list entry. If post-free traversal is confirmed, reclassify the issue as CLASS_B with `RealUAF=YES`.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: wifi: mac80211: unlist vifs when their netdev is unregistered [ Upstream
Commit: a22c02863439993095acd0c3db97fa53cd515f4f
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a22c02863439993095acd0c3db97fa53cd515f4f
Changed files:
net/wireless/core.h
net/mac80211/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=a22c02863439993095acd0c3db97fa53cd515f4f
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-98331 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98331
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:L/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: unknown
Paranoid ActionableScore: 2
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 [email protected] (and both
send reply to CVE record itself too and see "reply" button below for howto reply).
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