From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-46255][LOW] dmaengine: fsl-edma: don't explicitly disable clocks in .remove() [ Upstream Date: Wed, 03 Jun 2026 14:39:57 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-46255 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: 0 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: 533d495f15e4c88ad5246c7f90ae026702e28d75 List-Id: CVE: CVE-2026-46255 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: dmaengine: fsl-edma: don't explicitly disable clocks in .remove() [ Upstream Commit: 533d495f15e4c88ad5246c7f90ae026702e28d75 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=533d495f15e4c88ad5246c7f90ae026702e28d75 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46255 Analysis date: Wed, 03 Jun 2026 14:39:57 -0400 ActionableScore: 0 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate / Low-like Manual review required: NO Summary: fsl-edma manually disabled clocks that were already managed by devm_clk_get_enabled during driver removal, causing WARN messages and only a possible local privileged DoS on panic_on_warn systems. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-46255 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46255 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-2026-46255 LOW CHECK Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H';CWE-675;CWE-404;*CWE-664;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.4';DESCR 'fsl-edma disables mux clocks manually in fsl_edma_remove even though the clocks were obtained with devm_clk_get_enabled and are already managed by devres cleanup. Removing or unbinding the driver can therefore call clk disable and unprepare on clocks that are already disabled, producing kernel WARN messages. For the CVSS the PR:H is used because reliable triggering normally requires administrative control over driver removal or device unbind on the target. The issue is not network reachable and does not provide a memory corruption primitive. Impact is limited to local availability degradation or a kernel panic only on systems configured to panic on WARN.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 0) MAYBE HARDWARE LINUS MEMORY DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=0 ## 1. ActionableScore * Conservative score: 0 * Paranoid score: 0 * Final recommended bucket: **Ordinary Moderate / Low-like**:: ## 2. Signal breakdown * Requires admin/root/device-management privileges: -2 Triggering requires driver removal, module unload, or device unbind, which is normally restricted to host administrators. * Rare hardware/device-specific path: -1 The issue is specific to the fsl-edma DMA engine driver and relevant hardware/platforms. * No memory corruption signal: 0 The patch removes a redundant clock disable. It does not indicate UAF, double-free, OOB access, object confusion, or attacker-controlled overwrite. * No reliable ordinary crash signal: 0 The demonstrated symptom is WARN from clk_core_disable and clk_core_unprepare. A kernel panic is only possible on systems configured with panic_on_warn, so this is not counted as a general strong DoS. Raw score is negative, clamped to 0. ## 3. Reachability analysis The bug is reachable during fsl-edma driver removal or device unbind. In typical deployments this requires full administrative control over kernel modules, platform devices, or sysfs driver binding. It is not reachable remotely and not reachable by an ordinary local user. Namespaces or containers do not normally reduce the privilege requirement because host device unbind and driver removal are not delegated to unprivileged containers. Realistic exploitation is limited to producing kernel warnings during a privileged cleanup path, with possible DoS only on panic_on_warn systems. ## 4. Severity interpretation This behaves like a Low or ordinary Moderate cleanup bug, not an actionable Moderate or Important issue. The patch context shows duplicated resource cleanup for devm-managed clocks, resulting in warnings when already disabled or unprepared clocks are disabled again. There is no supported exploit primitive for memory corruption, privilege escalation, information disclosure, or cross-boundary access. The theoretical worst case is local privileged DoS if WARN is configured to panic the kernel. ## 5. One-sentence report phrase fsl-edma manually disabled clocks that were already managed by devm_clk_get_enabled during driver removal, causing WARN messages and only a possible local privileged DoS on panic_on_warn systems. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED This can be auto-closed for urgent security triage because it is a privileged device-removal warning path with no memory corruption, no remote reachability, no local unprivileged trigger, and no practical privilege escalation evidence. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: dmaengine: fsl-edma: don't explicitly disable clocks in .remove() [ Upstream Commit: 533d495f15e4c88ad5246c7f90ae026702e28d75 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=533d495f15e4c88ad5246c7f90ae026702e28d75 Changed files: drivers/clk/clk.c drivers/dma/fsl-edma-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=533d495f15e4c88ad5246c7f90ae026702e28d75 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-46255 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46255 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:L/PR:H/UI:N/S:U/C:N/I:N/A:L The Best / paranoid CVSS vector: AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS score: 4.4 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: 0 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).