From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-80936][LOW] wifi: mt76: mt7925: cancel mlo_pm_work on stop Date: Fri, 11 Sep 2026 18:19:03 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-80936 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: unknown X-AL-KERNEL-Commit: 304470333b7f525b23699ea7a7aed3b40ca37ca9 List-Id: CVE: CVE-2026-80936 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: wifi: mt76: mt7925: cancel mlo_pm_work on stop Commit: 304470333b7f525b23699ea7a7aed3b40ca37ca9 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=304470333b7f525b23699ea7a7aed3b40ca37ca9 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80936 Analysis date: Fri, 11 Sep 2026 18:19:03 -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-2026-80936 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80936 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-2026-80936 LOW https://www.kernelcve.org/list/?q=CVE-2026-80936 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-664;*CWE-672;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.7';DESCR 'mt7925 queues mlo_pm_work with a 5 second delay during multi-link power-save setup but the work was not cancelled when the device stop path ran. If the device is torn down inside that timing window, the delayed work can outlive teardown and later try to queue on a workqueue that is already gone, producing a kernel workqueue warning and possible denial of service in systems that treat warnings as fatal. For the CVSS the PR:L is used in the paranoid score because some deployments may delegate local network device control or equivalent WiFi management capability to non-root users or service accounts. The issue is not directly network reachable and requires local control over device stop, suspend, reset, removal, or a similar management path. Impact is primarily availability loss, with no concrete evidence of information disclosure, privilege escalation, or arbitrary memory corruption from the patch context.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2) YES REMOTE DANGER SIMPLEFIX NETWORK HARDWARE 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 PrimitiveClass=CLASS_B RealUAF=YES HostAdminRequired=UNKNOWN NamespaceScopedPrivilege=NO ImportantCandidate=NO ManualReview=NO AutoDowngradeAllowed=YES 1. ActionableScore * Raw conservative score: 2 * Conservative score: 2 * Raw paranoid score: 2 * Paranoid score: 2 * Final recommended bucket: **Ordinary Moderate**:: No floor or cap changed the score. Real UAF floor 4 is not applied because this is a constrained async teardown case with a shallow workqueue warning path and no demonstrated meaningful reuse, refcount mutation, callback hijack, disclosure, or controlled corruption. 2. Signal breakdown Positive signals: * +2 Real UAF / lifetime violation. The delayed mlo_pm_work can outlive the mt7925 stop or teardown path and later try to use a workqueue that has already gone away. Non-awarded signals: * +0 Reliable kernel crash / strong DoS. The supplied evidence shows a kernel workqueue WARNING, not a demonstrated panic or host-wide crash. * +0 Extra availability impact. panic_on_warn could make the warning fatal in some deployments, but that is a deployment-specific hardening setting and is not counted as an independent default impact. * +0 Structured stale-object leverage. The stale operation is a shallow delayed-work requeue attempt after teardown, not meaningful consumption of attacker-controlled structured fields. * +0 Weak LPE concern. No controlled reclaim, attacker-shaped replacement object, callback control, arbitrary read/write, or privilege escalation path is established. * +0 Concrete repeated release/refcount. No first put/free followed by a second put/free/refcount mutation on the exact same dangling reference is shown. * +0 Remote reachability. The vulnerable operation is a local device stop/teardown path, not packet-triggered. * +0 Local unprivileged trigger. Ordinary unprivileged reachability is not established. * +0 Hardware rarity penalty. mt7925 is hardware-specific, but the evidence does not establish rare or physical-only attack requirements beyond having the affected device. Negative signals: * No negative points applied. Host-admin-equivalent privilege is not positively established for every possible stop/suspend path, so no -2 host-admin penalty is applied. A hard timing penalty is not applied because the five second delayed-work window is explicit and not shown to be narrow or externally uncontrollable. 3. Reachability analysis The trigger requires mt7925 multi-link power-save setup to queue mlo_pm_work and then a local stop, suspend, reset, removal, or teardown path before the delayed work fires. The most realistic actor is a local system component or user with delegated WiFi or network-device management rights, but the supplied evidence does not prove that an ordinary unprivileged user can complete the full trigger. HostAdminRequired is UNKNOWN. Administrative control is plausible for interface stop or device teardown, but the prompt requires positive evidence before setting host-admin required to YES. NamespaceScopedPrivilege is NO because this concerns a physical mt7925 WiFi device path, and the supplied evidence does not show a complete attacker-created namespace trigger. There is no direct network trigger. Remote WiFi traffic alone is not shown to stop the device or schedule the teardown sequence. No prior special sysctl or boot option is shown. The race/timing aspect is bounded by a five second delayed-work window, but the evidence does not show an especially hard one-shot race. 4. Primitive and severity interpretation The primitive is a constrained asynchronous lifetime violation: delayed work remains pending after the owning device/workqueue teardown path begins or completes. This is closer to fixed async stale storage than to an attacker-controlled active structured object UAF. The demonstrated consequence is a workqueue WARNING when the delayed timer fires and attempts to queue mt7925_mlo_pm_work on a gone workqueue. A fatal DoS is possible only in configurations that treat warnings as fatal, but a normal kernel crash is not established by the supplied data. No concrete repeated release/refcount operation exists. There is no evidence that an earlier release can free an object and that the exact same dangling reference later receives a second lifetime-mutating put/free/refcount operation. This is therefore not the stronger double-release Class B case. PrimitiveClass is CLASS_B because a real async post-teardown lifetime violation is directly implied. It remains constrained because there is no controlled reclaim, no arbitrary or directed memory access, no callback/function-pointer consumption, no information disclosure, no security-boundary bypass, and no privilege escalation evidence. ImportantCandidate is NO because the established impact is a constrained warning/possible DoS path without meaningful unresolved exploitation leverage. AutoDowngradeAllowed is YES because automatic downgrade would not discard a concrete Important-grade primitive. 5. One-sentence report phrase mt7925 delayed mlo_pm_work was not cancelled on stop, allowing pending work to outlive device teardown and later hit a workqueue warning, with practical impact limited to local availability risk and no demonstrated privilege escalation or memory corruption leverage. 6. Manual review recommendation NO MANUAL CHECK NEEDED The issue is a constrained driver teardown lifetime bug with a demonstrated warning path only, no network reachability, no concrete repeated refcount/free mutation, and no evidence of C/I impact or LPE. 7. Call-site confidence Call-site confidence: high ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: wifi: mt76: mt7925: cancel mlo_pm_work on stop Commit: 304470333b7f525b23699ea7a7aed3b40ca37ca9 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=304470333b7f525b23699ea7a7aed3b40ca37ca9 Commit description: mt7925 queues mlo_pm_work with a 5 second delay during multi-link power-save setup and never cancels it on the stop path. If the device is torn down inside that window, the work outlives the teardown and its timer fires afterwards, trying to queue onto the workqueue that is already gone: workqueue: cannot queue mt7925_mlo_pm_work [mt7925_common] on wq phy0 WARNING: kernel/workqueue.c:2283 at __queue_work+0x59/0xa0, CPU#1: swapper/1/0 call_timer_fn+0x2a/0x140 __run_timers+0x203/0x330 run_timer_softirq+0x86/0xf0 mt7921 already has its own stop callback, so add one for mt7925 that cancels the work before calling mt792x_stop(). mt7925_ops backs both the PCIe and USB drivers, so this covers both. Fixes: 276a568 ("wifi: mt76: mt7925: update the power-saving flow") Cc: stable@vger.kernel.org Tested-by: Traockl <281473483+Traockl@users.noreply.github.com> Signed-off-by: Devin Wittmayer Link: https://patch.msgid.link/20260627202946.25598-1-lucid_duck@justthetip.ca Signed-off-by: Felix Fietkau Signed-off-by: Greg Kroah-Hartman Changed files: kernel/workqueue.c drivers/net/wireless/mediatek/mt76/mt7925/main.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=304470333b7f525b23699ea7a7aed3b40ca37ca9 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-80936 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80936 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:L 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: 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: 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).