From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-64170][MODERATE REGULAR] spi: qup: fix error pointer deref after DMA setup failure [ Upstream Date: Sun, 19 Jul 2026 13:08:34 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-64170 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: 2 X-AL-KERNEL-Commit: 0bb3bd442f0bdad3932739a61dd6c580c9c1955e List-Id: CVE: CVE-2026-64170 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: spi: qup: fix error pointer deref after DMA setup failure [ Upstream Commit: 0bb3bd442f0bdad3932739a61dd6c580c9c1955e Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0bb3bd442f0bdad3932739a61dd6c580c9c1955e Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64170 Analysis date: Sun, 19 Jul 2026 13:08:34 -0400 ActionableScore: 3 ActionableScore lower bound: 2 Actionable bucket: Borderline manual review recommended Manual review required: YES Summary: A stale DMA channel pointer in the spi-qup probe error path can lead to an error pointer dereference or second DMA channel release during later cleanup or driver unbind, causing a local privileged DoS with only weak corruption concern. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-64170 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64170 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-2026-64170 MODERATE CHECK WITH IMPACT FROM ORIG NN LOW Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:H';**CWE-476;CWE-415;CWE-754;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.2';DESCR 'spi qup can keep stale DMA channel pointers after DMA setup fails during probe. Later probe error handling or driver unbind can then dereference an error pointer or attempt to release the same DMA channel again, which may crash the kernel. For the CVSS the PR:H is used for the paranoid score because reliable triggering normally requires administrative control over driver bind/unbind, probe failure conditions, or platform device management. The issue is not network reachable and is specific to systems using the QUP SPI controller with DMA enabled. Impact is primarily local denial of service, with limited confidentiality or integrity concern only in the conservative case because a second release path is mentioned.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline manual review recommended (with actual score 3) YES INIT SIMPLEFIX DMAorINTERRUPT MEMORY DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=3 ActionableScoreLower=2 ## 1. ActionableScore * Conservative score: 2 * Paranoid score: 3 * Final recommended bucket: **Borderline manual review recommended**:: ## 2. Signal breakdown Conservative signals: * Weak/indirect corruption candidate: +1 `host->dma_tx` and `host->dma_rx` may remain as stale or error-valued pointers after DMA setup failure. Later paths may dereference or release them. * Real lifetime corruption: +1 The patch fixes stale DMA channel pointer lifetime after `dma_release_channel()`. * Reliable kernel crash / strong DoS: +1 The commit explicitly mentions error pointer dereference and possible second release on later probe errors or driver unbind. * Requires admin/root/CAP_* in typical deployments: -2 Reliable triggering normally requires control over driver probe, unbind, platform device management, or DMA setup failure conditions. Paranoid additional signal: * Weak LPE concern: +1 A second release of a DMA channel is a corruption sink worth manual review, but no attacker-controlled reclaim, overwrite, callback control, or object replacement is shown. Not counted: * No remote/network reachability. * No strong memory corruption primitive. * No strong privilege escalation evidence. * No confidentiality or integrity impact in the conservative score. ## 3. Reachability analysis The bug is local and platform-specific. It affects systems using the Qualcomm QUP SPI controller with DMA support. A practical trigger requires DMA setup failure during probe and then a later probe error path or driver unbind that observes stale DMA pointers. In typical deployments, unbinding drivers, forcing probe paths, or controlling platform DMA failure conditions requires administrative privileges. Namespaces or containers normally do not reduce this requirement unless the environment delegates device management to a less privileged actor. This is not reachable through packet traffic or a normal remote interface. Call-site confidence: medium. The patch shows the cleanup site and the commit message states the later probe error or unbind consequence, but full caller context is not included. ## 4. Severity interpretation This behaves more like a low-to-borderline Moderate kernel driver DoS than an Important vulnerability. The realistic impact is a local crash or device-management failure under specific error-path conditions. The theoretical concern is that a second `dma_release_channel()` could represent a weak lifetime/corruption issue. However, the patch does not show attacker-controlled reuse, arbitrary write, type confusion, callback dispatch, or a practical privilege escalation path. Therefore the paranoid score is only slightly raised for manual-review sensitivity. ## 5. One-sentence report phrase A stale DMA channel pointer in the spi-qup probe error path can lead to an error pointer dereference or second DMA channel release during later cleanup or driver unbind, causing a local privileged DoS with only weak corruption concern. ## 6. Manual review recommendation MANUAL CHECK RECOMMENDED Reason: the issue is admin-gated and device-specific, but the commit explicitly mentions a possible second release of a DMA channel, so it should not be blindly auto-closed without a quick driver-lifetime review. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: spi: qup: fix error pointer deref after DMA setup failure [ Upstream Commit: 0bb3bd442f0bdad3932739a61dd6c580c9c1955e Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0bb3bd442f0bdad3932739a61dd6c580c9c1955e Changed files: drivers/spi/spi-qup.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=0bb3bd442f0bdad3932739a61dd6c580c9c1955e ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-64170 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64170 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:H/PR:H/UI:N/S:U/C:L/I:L/A:H The Best / paranoid CVSS score: 5.2 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: 2 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).