* [CVE-2026-90398][MODERATE 7.0] wifi: ath11k: fix stride mismatch in mac_phy_caps_parse() [ Upstream
@ 2026-09-18 6:24 21% AL-KERNEL
0 siblings, 0 replies; 1+ results
From: AL-KERNEL @ 2026-09-18 6:24 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-90398
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: wifi: ath11k: fix stride mismatch in mac_phy_caps_parse() [ Upstream
Commit: bbb3b3334a9ed850c5b332eedea107796e691237
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bbb3b3334a9ed850c5b332eedea107796e691237
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90398
Analysis date: Fri, 18 Sep 2026 02:24:29 -0400
ActionableScore: 6
ActionableScore lower bound: 5
Actionable bucket: Actionable Moderate / Strong Important candidate requiring manual review
Manual review required: YES
Summary:
No one-sentence report phrase was found.
======================================================================
ABOUT THIS REPORT
======================================================================
The original Linux kernel CVE announcement for CVE-2026-90398 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90398
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.
======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================
CVE-2026-90398 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-90398 CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H';*CWE-787;CWE-131;*CWE-20;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '6.8';DESCR 'A heap out of bounds write can occur in ath11k mac_phy_caps parsing because the allocation size used the firmware provided TLV length while later accesses used the full struct wmi_mac_phy_capabilities pointer stride. If a short firmware TLV is accepted, the second and later mac_phy_caps slots are written beyond the allocated buffer during memcpy. This is kernel memory corruption rather than a simple warning or resource leak. For the CVSS the PR:N is used in the paranoid score only for the malicious device or firmware controlled input case where no host user account is required. The issue is not proven to be directly reachable from ordinary WiFi network traffic because the malformed input is a firmware WMI service ready TLV. Impact is at least denial of service via kernel crash and in worst case may allow confidentiality or integrity impact due to controlled heap corruption.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate / Strong Important candidate requiring manual review (with actual score 6) YES REMOTE SIMPLEFIX NETWORK LINUS TEST KPANIC KPANIC INCREASED_TO_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFKP NO NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=6
ActionableScoreLower=5
PrimitiveClass=CLASS_A
RealUAF=NO
HostAdminRequired=NO
NamespaceScopedPrivilege=NO
ImportantCandidate=YES
ManualReview=REQUIRED
AutoDowngradeAllowed=NO
1. ActionableScore
* Raw conservative score: 4
* Conservative score: 5
* Applied conservative floor/cap: 4 -> 5 due to established controlled kernel heap out of bounds write requiring manual triage.
* Raw paranoid score: 6
* Paranoid score: 6
* Final recommended bucket: **Actionable Moderate / Strong Important candidate requiring manual review**::
2. Signal breakdown
Conservative signals:
* +2 Strong corruption primitive. The patch establishes a real heap out of bounds write: allocation used `tot_phy_id * len`, while later destination indexing used `sizeof(struct wmi_mac_phy_capabilities)` stride.
* +1 Firmware-mediated external influence. The malformed short TLV is supplied through ath11k firmware WMI service-ready parsing, so firmware or device mediation is material.
* +1 Reliable kernel crash / strong DoS. A kernel heap overwrite during `memcpy()` can corrupt adjacent heap state and realistically crash the host kernel.
* +0 Memory layout invariant restoration not separately awarded. The allocation-size versus pointer-stride mismatch is the same fact as the OOB write.
* +0 Direct network reachability not awarded. The vulnerable input is a firmware WMI TLV, not ordinary WiFi packet processing.
* +0 RealUAF not awarded. This is an OOB write, not a lifetime bug.
* +0 C/I not conservatively awarded as separate consequence. The patch proves heap corruption, but not a demonstrated disclosure, arbitrary write, credential overwrite, or LPE chain.
Paranoid signals:
* +2 Strong corruption primitive.
* +1 Firmware-mediated external influence.
* +1 Reliable kernel crash / strong DoS.
* +2 Strong exploitation leverage in the paranoid interpretation. The overwrite is not just a NULL dereference or warning: firmware-controlled TLV size and copied bytes can drive a heap overwrite across multiple array slots. Controlled reclaim, target selection, and LPE are not demonstrated, so this remains bounded at 6 rather than 7+.
Negative signals:
* No -2 host-admin penalty. Host-admin-equivalent privilege is not positively required when the attacker model is malicious or compromised firmware/device input.
* No physical-only or rare-hardware penalty. ath11k is hardware-specific, but the supplied evidence does not establish rare physical access as the only realistic prerequisite.
* No race penalty. This is deterministic allocation/copy stride mismatch, not a timing race.
* No extra Availability point. The same heap corruption/crash is already counted once.
3. Reachability analysis
The direct malformed input source is ath11k firmware WMI TLV data. A normal remote WiFi peer is not shown to be able to send this TLV directly into `ath11k_wmi_tlv_mac_phy_caps_parse()`, so direct network reachability is not established.
The plausible attacker model is malicious, compromised, or attacker-influenced firmware/device behavior. Under that model, no host user account or host administrator privilege is needed on the victim system, but the trigger is firmware-mediated rather than a normal network packet path.
Namespace-scoped privilege is not relevant. There is no evidence that user or network namespaces affect reachability. There is no race requirement. The bug is reachable during WMI service-ready capability parsing when multiple MAC/PHY capability TLVs are processed and one or more TLVs are shorter than the full structure size.
4. Primitive and severity interpretation
The exact primitive is a firmware-influenced kernel heap out of bounds write caused by inconsistent allocation and indexing stride. The allocated array used the clamped TLV length as element size, but the pointer arithmetic later advanced by the full structure size.
This is active kernel heap corruption, not fixed stale storage, not a cleanup-only stale dereference, and not a resource leak. No concrete repeated release/refcount operation exists. The demonstrated consequence is memory corruption with likely DoS. The speculative consequence is privilege escalation or broader C/I impact if adjacent heap objects can be shaped or meaningfully corrupted, but controlled reclaim, arbitrary read/write, function-pointer control, or LPE is not established by the patch.
PrimitiveClass is CLASS_A because an attacker-influenced OOB write into kernel heap memory is directly established. ImportantCandidate is YES because kernel heap overwrite with firmware-controlled input needs manual Important-vs-Moderate review. AutoDowngradeAllowed is NO because automatically closing a controlled kernel heap corruption primitive would risk a false-negative downgrade.
5. One-sentence report phrase
A firmware-mediated stride mismatch in ath11k WMI MAC PHY capability parsing can under-allocate `mac_phy_caps` and then write later entries past the heap buffer, causing kernel memory corruption and likely DoS, with possible higher impact requiring manual review.
6. Manual review recommendation
MANUAL CHECK REQUIRED
Reason: this is a concrete kernel heap out of bounds write with firmware-controlled input properties, not a crash-only validation bug or resource leak.
7. Call-site confidence
Call-site confidence: high
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: wifi: ath11k: fix stride mismatch in mac_phy_caps_parse() [ Upstream
Commit: bbb3b3334a9ed850c5b332eedea107796e691237
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bbb3b3334a9ed850c5b332eedea107796e691237
Changed files:
drivers/net/wireless/ath/ath11k/wmi.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=bbb3b3334a9ed850c5b332eedea107796e691237
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-90398 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90398
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:L/I:L/A:H
The Best / paranoid CVSS vector: AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
The Best / paranoid CVSS score: 6.8
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: 5
Paranoid ActionableScore: 6
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 [email protected] (and both
send reply to CVE record itself too and see "reply" button below for howto reply).
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