* [CVE-2026-90084][LOW] octeontx2-vf: fix workqueue and netdev race in probe/remove [ Upstream
@ 2026-09-18 11:02 21% AL-KERNEL
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From: AL-KERNEL @ 2026-09-18 11:02 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-90084
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: octeontx2-vf: fix workqueue and netdev race in probe/remove [ Upstream
Commit: 42a139332ce81a907dac987f1494d30e0a8ab149
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=42a139332ce81a907dac987f1494d30e0a8ab149
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90084
Analysis date: Fri, 18 Sep 2026 07:02:02 -0400
ActionableScore: 2
ActionableScore lower bound: 1
Actionable bucket: Ordinary Moderate
Manual review required: NO
Summary:
octeontx2 VF may register a netdev before initializing its workqueue, allowing rx mode changes in a narrow probe window to queue work on a NULL workqueue and cause a local kernel crash.
======================================================================
ABOUT THIS REPORT
======================================================================
The original Linux kernel CVE announcement for CVE-2026-90084 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90084
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: LOW
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-2026-90084 LOW https://www.kernelcve.org/list/?q=CVE-2026-90084 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:N/I:N/A:H';CWE-362;**CWE-476;CWE-703;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '4.7';DESCR 'octeontx2 VF can expose a netdev before its VF workqueue is initialized, creating a race where ndo_set_rx_mode may queue work on a NULL workqueue during probe. This can result in a NULL-pointer dereference and a kernel crash when rx mode changes occur in the narrow registration window or during related cleanup paths. For the CVSS the PR:L is used for the paranoid score because a delegated network administrator or reduced capability service with CAP_NET_ADMIN may be able to influence netdev state without full host root. The issue is not directly network reachable because incoming packets do not normally change the rx mode list by themselves. Impact is denial of service only, with no clear evidence of information disclosure or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2) YES REMOTE INIT SIMPLEFIX RACE NETWORK LINUS DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 YES NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=2
ActionableScoreLower=1
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES
## 1. ActionableScore
* Raw conservative score: 1
* Conservative score: 1. No floor or cap applied.
* Raw paranoid score: 2
* Paranoid score: 2. No floor or cap applied.
* Final recommended bucket: **Ordinary Moderate**::
## 2. Signal breakdown
Conservative signals:
* +1. Weak invalid-state / NULL pointer class issue. The netdev may be registered before `vf->otx2_wq` is initialized, allowing `ndo_set_rx_mode` to queue work on a NULL workqueue.
* +1. Reliable kernel crash / strong DoS. A NULL workqueue dereference can plausibly crash the kernel.
* -1. Narrow probe/remove ordering race. The vulnerable window is during driver probe or cleanup ordering, not a broad steady-state packet-processing path.
Raw conservative score: 1.
Paranoid signals:
* +1. Weak invalid-state / NULL pointer class issue.
* +1. Reliable kernel crash / strong DoS.
* 0. No race penalty in the paranoid score because repeated probe/remove or management activity may make the ordering issue more reachable in some environments.
Raw paranoid score: 2.
Important non-awarded signals:
* RealUAF not awarded. The supplied patch establishes NULL workqueue use, not a freed object dereference.
* Concrete repeated release/refcount not awarded. There is no visible first release followed by a second lifetime mutation on the same dangling reference.
* Structured stale-object leverage not awarded. No stale structured object reuse or meaningful post-free field consumption is established.
* Weak LPE and Strong LPE not awarded. No controlled reclaim, arbitrary write, callback control, credential manipulation, or privilege escalation primitive is shown.
* C/I impact not awarded. The evidence supports DoS only.
* Remote reachability not awarded. Incoming packets do not normally trigger the vulnerable workqueue ordering directly.
* Extra availability not awarded. The kernel crash is already counted once.
## 3. Reachability analysis
The issue is in a Marvell octeontx2 VF Ethernet driver probe/remove path. The vulnerable condition appears when the netdev becomes visible through `register_netdev()` before the VF workqueue is initialized, allowing `ndo_set_rx_mode` to run in the registration window.
A fully reliable attacker path is not established from the supplied evidence. Driver probe/remove and PCI VF lifecycle are commonly controlled by host administration or device management, but the exact complete trigger could also involve delegated network management that changes multicast or promiscuous mode. Because the full privilege boundary is unresolved, `HostAdminRequired=UNKNOWN` is used rather than assuming host admin or below-host-admin reachability.
Namespace-scoped privilege is also unresolved. A network namespace or CAP_NET_ADMIN possibility alone does not prove that the complete operation is namespace-scoped, especially for a physical or host-owned VF device.
No direct network trigger is established. Packet traffic alone is not shown to invoke the vulnerable setup ordering. No special rare hardware penalty is applied beyond noting that the bug is driver-specific, because driver-specific code is not automatically rare enough for a scoring penalty.
Race repeatability is limited by probe/remove or initialization timing, so the conservative score treats the race as narrow. The paranoid score withholds that penalty because management actions may allow repeated attempts.
## 4. Primitive and severity interpretation
The exact primitive is a NULL pointer dereference through a missing or not-yet-initialized workqueue pointer. This is an invalid-state crash primitive, not a use-after-free and not a concrete memory corruption primitive.
The object involved is an active driver/netdev structure, but the stale-use rules do not apply because the issue is not shown as post-free reuse. The demonstrated consequence is denial of service through kernel crash. The speculative consequence of privilege escalation is not supported by the patch or supplied context.
PrimitiveClass is `CLASS_C` because the behavior is primarily crash/DoS from an invalid state. ImportantCandidate is `NO` because no unresolved meaningful exploitation leverage beyond crash is established. AutoDowngradeAllowed is `YES` because this is a constrained crash-only driver ordering bug with no demonstrated UAF, repeated refcount mutation, authorization bypass, controlled corruption, or C/I impact.
Likely operational severity is ordinary Moderate or Low-like depending on deployment, with practical concern mainly for systems using this VF driver and allowing relevant management operations during device initialization or removal.
## 5. One-sentence report phrase
octeontx2 VF may register a netdev before initializing its workqueue, allowing rx mode changes in a narrow probe window to queue work on a NULL workqueue and cause a local kernel crash.
## 6. Manual review recommendation
NO MANUAL CHECK NEEDED
Reason: the supplied evidence supports a constrained NULL pointer DoS only, with no UAF, no repeated lifetime mutation, no direct network trigger, and no privilege escalation primitive.
## 7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: octeontx2-vf: fix workqueue and netdev race in probe/remove [ Upstream
Commit: 42a139332ce81a907dac987f1494d30e0a8ab149
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=42a139332ce81a907dac987f1494d30e0a8ab149
Changed files:
drivers/net/ethernet/marvell/octeontx2/nic/otx2_vf.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=42a139332ce81a907dac987f1494d30e0a8ab149
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-90084 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90084
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:N/I:N/A:H
The Best / paranoid CVSS score: 4.7
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: 1
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: LOW
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): LOW
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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