* [CVE-2026-90399][MODERATE 7.0] wifi: ath12k: fix stride mismatch in mac_phy_caps_parse() [ Upstream
@ 2026-09-18 10:58 21% AL-KERNEL
0 siblings, 0 replies; 1+ results
From: AL-KERNEL @ 2026-09-18 10:58 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-90399
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: wifi: ath12k: fix stride mismatch in mac_phy_caps_parse() [ Upstream
Commit: d3355e0fdbbf531ca8b82a6a3feb80a1b7306a8b
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d3355e0fdbbf531ca8b82a6a3feb80a1b7306a8b
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90399
Analysis date: Fri, 18 Sep 2026 06:58:39 -0400
ActionableScore: 5
ActionableScore lower bound: unknown
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-2026-90399 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90399
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-2026-90399 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-90399 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-122;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '6.8';DESCR 'An OOB write in ath12k WMI mac_phy_caps_parse can occur when firmware sends short mac phy capability TLVs. The buffer was allocated using tot_phy_id multiplied by a clamped TLV length, while later slots are addressed using full struct pointer stride, so the second and later entries can be copied past the allocation. For the CVSS the PR:N value is used for the paranoid hardware or firmware controlled scenario, because a malicious or compromised device can provide malformed WMI TLVs without a host user account. The issue is not normally reachable from ordinary Wi-Fi network traffic and practical exploitation usually requires control of firmware, a malicious device, or a privileged path that can alter firmware behavior. Impact is kernel memory corruption with at least denial of service and a plausible worst case of confidentiality and integrity impact if the overflow is made controllable.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate / Strong Important candidate requiring manual review (with actual score 5) YES REMOTE SIMPLEFIX NETWORK HARDWARE LINUS KPANIC NO NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=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: manual-review safety floor for concrete kernel heap OOB write: 4 -> 5
* Raw paranoid score: 5
* Paranoid score: 5
* Applied paranoid floor/cap: none
* Final recommended bucket: **Actionable Moderate / Strong Important candidate requiring manual review**::
2. Signal breakdown
Positive signals:
* +2: Strong kernel corruption primitive. The patch directly establishes a heap out-of-bounds write because allocation used `tot_phy_id * len`, while later writes used full-struct pointer stride.
* +1: Firmware-mediated external influence. The malformed short TLVs are provided by ath12k firmware or device-side WMI data, not ordinary host userspace.
* +1: Reliable kernel crash / strong DoS is realistic. A kernel heap OOB write during driver initialization can corrupt adjacent heap data and plausibly crash the host.
* +1 paranoid only: Weak exploitation leverage concern. The copied bytes and short TLV length are firmware-controlled, so the overwrite is not merely a fixed zero write, but controlled target selection or reclaim is not demonstrated.
Negative or non-awarded signals:
* Controlled reclaim is not demonstrated.
* Arbitrary or directed kernel write is not demonstrated.
* RealUAF is NO. This is an allocation-size and pointer-stride mismatch, not a lifetime bug.
* Remote Wi-Fi packet reachability is not established. The input is firmware-mediated WMI data.
* No local unprivileged host trigger is established.
* No namespace-scoped privilege path applies.
* No separate confidentiality or integrity point is awarded beyond the corruption primitive, because no disclosure path, credential overwrite, protected object modification, or LPE chain is demonstrated.
* No rare-hardware penalty is applied merely because this is a Wi-Fi driver. The issue is hardware/firmware mediated, but the patch does not prove an uncommon physical-only requirement sufficient for a reducing penalty.
* No extra availability point is awarded beyond the same kernel crash/corruption consequence.
Arithmetic:
* Conservative raw: +2 strong OOB write +1 firmware-mediated influence +1 strong DoS = 4.
* Conservative final: 5 after safety floor for concrete kernel heap OOB write requiring manual review.
* Paranoid raw: +2 strong OOB write +1 firmware-mediated influence +1 strong DoS +1 weak exploitation leverage concern = 5.
* Paranoid final: 5.
3. Reachability analysis
The vulnerable parser handles ath12k WMI MAC/PHY capability TLVs supplied by firmware during service-ready capability processing. A normal local user is not shown to be able to directly craft these TLVs. Ordinary Wi-Fi network traffic is also not shown to directly reach this parsing path.
The realistic attacker model is firmware-mediated: compromised firmware, a malicious device, or a privileged path that can alter firmware behavior can provide short TLVs and trigger the allocation/stride mismatch. This does not require host-admin privileges in the malicious-device model, but it does require control over the device/firmware data source rather than simple network reachability.
No namespace capability is involved. No race is involved. The issue appears deterministic once malformed short TLVs and multiple capability slots are processed.
4. Primitive and severity interpretation
The exact primitive is a kernel heap out-of-bounds write. The buffer is allocated using a length derived from the short TLV size, but later slots are addressed using `struct ath12k_wmi_mac_phy_caps_params` pointer arithmetic. Therefore slot 2 and later can be copied beyond the allocation when `len` is smaller than the full structure size.
This is active kernel memory corruption, not a NULL dereference, not a resource leak, and not a UAF. The demonstrated consequence is memory corruption with realistic DoS. The speculative consequence is stronger exploitation if the firmware-controlled overflow can be shaped against useful adjacent heap objects, but controlled reclaim, arbitrary write, information disclosure, or privilege escalation is not established by the supplied evidence.
PrimitiveClass is CLASS_A because an attacker-influenced heap OOB write is directly established under the firmware/device attacker model. ImportantCandidate is YES because concrete kernel heap corruption should not be automatically downgraded. AutoDowngradeAllowed is NO because automatic closure would discard a real unresolved kernel corruption primitive.
Likely operational severity: Actionable Moderate at minimum, with manual review required for Important classification depending on product exposure to untrusted firmware/device inputs.
5. One-sentence report phrase
A firmware-mediated stride mismatch in ath12k WMI capability parsing can allocate `mac_phy_caps` too small and then copy later full-stride entries past the heap allocation, causing kernel memory corruption and possible DoS with unresolved exploitability beyond crash.
6. Manual review recommendation
MANUAL CHECK REQUIRED
Concrete kernel heap OOB write is established, and the overwrite source is firmware-controlled enough to require manual review even though ordinary remote network reachability and full LPE are not demonstrated.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: wifi: ath12k: fix stride mismatch in mac_phy_caps_parse() [ Upstream
Commit: d3355e0fdbbf531ca8b82a6a3feb80a1b7306a8b
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d3355e0fdbbf531ca8b82a6a3feb80a1b7306a8b
Changed files:
drivers/net/wireless/ath/ath12k/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=d3355e0fdbbf531ca8b82a6a3feb80a1b7306a8b
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-90399 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90399
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: unknown
Paranoid ActionableScore: 5
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).
^ permalink raw reply [relevance 21%]
Results 1-1 of 1 | reverse | sort options + mbox downloads above
-- links below jump to the message on this page --
2026-09-18 10:58 21% [CVE-2026-90399][MODERATE 7.0] wifi: ath12k: fix stride mismatch in mac_phy_caps_parse() [ Upstream AL-KERNEL
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox