From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-90084][LOW] octeontx2-vf: fix workqueue and netdev race in probe/remove [ Upstream Date: Fri, 18 Sep 2026 07:02:02 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-90084 X-AL-KERNEL-Priority: LOW X-AL-KERNEL-Severity: LOW X-AL-KERNEL-Base-Severity: LOW X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 2 X-AL-KERNEL-ActionableScore-Lower: 1 X-AL-KERNEL-Commit: 42a139332ce81a907dac987f1494d30e0a8ab149 List-Id: 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 alexanjelausa@gmail.com (and both send reply to CVE record itself too and see "reply" button below for howto reply).