From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-45996][MODERATE REGULAR] spi: imx: fix use-after-free on unbind Date: Wed, 27 May 2026 17:36:13 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-45996 X-AL-KERNEL-Priority: MODERATE REGULAR X-AL-KERNEL-Severity: MODERATE REGULAR X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 3 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: f99165ef067723221472ce1aff632bc74f562643 List-Id: CVE: CVE-2026-45996 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: spi: imx: fix use-after-free on unbind Commit: f99165ef067723221472ce1aff632bc74f562643 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f99165ef067723221472ce1aff632bc74f562643 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-45996 Analysis date: Wed, 27 May 2026 17:36:13 -0400 ActionableScore: 3 ActionableScore lower bound: unknown Actionable bucket: Borderline, manual review recommended Manual review required: YES Summary: No one-sentence report phrase was found. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-45996 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-45996 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 REGULAR 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-2026-45996 MODERATE 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:H/I:H/A:H';*CWE-416;*CWE-664;*CWE-672;CWE-703;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '6.7';DESCR 'spi_imx_remove() can keep using spi_imx driver data after spi_unregister_controller() has deregistered and potentially freed the controller and its subsystem allocated private data. This creates a use after free during driver unbind or remove, with later runtime PM and SDMA cleanup touching freed memory. For the CVSS the PR:H is used because reliable triggering normally requires administrator level device management such as platform driver unbind or module removal. The issue is not network reachable and is not exposed through a normal user data path. Impact is mainly local denial of service during device removal, with higher confidentiality and integrity impact kept only for the paranoid score because the bug class is UAF in kernel driver cleanup.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline, manual review recommended (with actual score 3) MAYBE UAF HARDWARE DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=3 1. ActionableScore * Conservative score: 3 * Paranoid score: 3 * Final recommended bucket: **Borderline, manual review recommended**:: 2. Signal breakdown * Generic memory corruption: +2. The patch fixes a real use-after-free of `spi_imx` / controller private data after `spi_unregister_controller()`. * Real lifetime corruption: +1. The root cause is object lifetime mismatch during controller deregistration and later driver cleanup. * Reliable kernel crash / DoS: +1. Accessing freed driver data during unbind can crash the kernel. * Requires admin/root/device-management control: -2. Reliable triggering normally requires platform driver unbind, module removal, or equivalent device-management privilege. * Rare hardware/configuration exposure: -1. The affected path is specific to i.MX SPI controller hardware and the remove/unbind path. * No remote or normal unprivileged data path. No evidence of attacker-controlled payload, reclaim primitive, or practical LPE is shown. 3. Reachability analysis The bug is reachable during i.MX SPI driver remove or unbind. In typical deployments, only an administrator or host-level device manager can trigger this path. Containers generally do not lower privileges unless they are granted dangerous device-management access. The issue is not network reachable and is not triggered through ordinary SPI user I/O. Exploitation beyond crash would require control over timing and freed-object reuse in a privileged cleanup path, which is not demonstrated. 4. Severity interpretation This is a real UAF, so it should not be dismissed solely as a cleanup bug. However, it behaves more like a privileged device-management DoS than an Important-class LPE because the trigger normally requires admin-level unbind/removal and the patch does not show a controlled reclaim or overwrite primitive. It is borderline and worth manual awareness, but not a strong Important candidate. 5. One-sentence report phrase The i.MX SPI remove path can use controller private data after `spi_unregister_controller()` frees it, causing a privileged unbind-time UAF and potential kernel crash. 6. Manual review recommendation MANUAL CHECK RECOMMENDED. The bug class is UAF, but practical exposure is limited to privileged i.MX SPI device unbind or removal with no demonstrated unprivileged or remote trigger. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: spi: imx: fix use-after-free on unbind Commit: f99165ef067723221472ce1aff632bc74f562643 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f99165ef067723221472ce1aff632bc74f562643 Commit description: The SPI subsystem frees the controller and any subsystem allocated driver data as part of deregistration (unless the allocation is device managed). Take another reference before deregistering the controller so that the driver data is not freed until the driver is done with it. Fixes: 307c897 ("spi: spi-imx: replace struct spi_imx_data::bitbang by pointer to struct spi_controller") Cc: stable@vger.kernel.org # 5.19 Acked-by: Marc Kleine-Budde Signed-off-by: Johan Hovold Link: https://patch.msgid.link/20260324082326.901043-2-johan@kernel.org Signed-off-by: Mark Brown Signed-off-by: Greg Kroah-Hartman Changed files: drivers/spi/spi-imx.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=f99165ef067723221472ce1aff632bc74f562643 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-45996 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-45996 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:H The Best / paranoid CVSS vector: AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H The Best / paranoid CVSS score: 6.7 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: 3 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: NO Published priority for this report (same as in Subject): MODERATE REGULAR 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).