From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-53061][MODERATE 7.0] dm cache: fix dirty mapping checking in passthrough mode switching [ Upstream Date: Wed, 24 Jun 2026 16:09:30 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-53061 X-AL-KERNEL-Priority: MODERATE 7.0 X-AL-KERNEL-Severity: MODERATE 7.0 X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 5 X-AL-KERNEL-ActionableScore-Lower: 3 X-AL-KERNEL-Commit: c2e86f647561fcf5e1c6eba7d75e9e0c4299c94d List-Id: CVE: CVE-2026-53061 Priority: MODERATE 7.0 AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: dm cache: fix dirty mapping checking in passthrough mode switching [ Upstream Commit: c2e86f647561fcf5e1c6eba7d75e9e0c4299c94d Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c2e86f647561fcf5e1c6eba7d75e9e0c4299c94d Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53061 Analysis date: Wed, 24 Jun 2026 16:09:30 -0400 ActionableScore: 5 ActionableScore lower bound: 3 Actionable bucket: Actionable Moderate at minimum Manual review required: NO Summary: dm-cache could allow dirty writeback cache mappings to enter passthrough mode during LVM table preload and resume ordering, allowing a local storage-management actor to cause persistent data loss or filesystem inconsistency. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-53061 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53061 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 7.0 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-2026-53061 MODERATE CHECK Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H';CWE-703;CWE-362;CWE-754;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:L';BEST CVSS score: '7.1';DESCR 'dm-cache passthrough mode could accept dirty cache mappings because the clean mapping check was performed during table creation while LVM table preload can occur before suspension and while metadata updates are still in progress. This is a control plane logic and state ordering issue rather than memory corruption. A local actor able to reload and resume a dm-cache table can cause dirty writeback cache blocks to be loaded into passthrough mode, which may result in data loss or filesystem inconsistency. For the CVSS the PR:L reflects a paranoid deployment model where a local non root user or delegated service can trigger dm table reloads through storage management tooling or reduced capability administration. The issue is not network reachable and does not provide a direct privilege escalation primitive. Impact is mainly integrity loss due to corrupted or lost stored data, with possible availability impact if the affected volume or filesystem becomes unusable.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 4) YES LOCK DISK IMPROVEONLY LINUS INCREASED_TO_MODERATE_FROM_LOW_BASED_ON_GUESSCVSS DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 NO YES checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=5 ActionableScoreLower=3 ## 1. ActionableScore * Conservative score: 3 * Paranoid score: 5 * Final recommended bucket: **Actionable Moderate at minimum** ## 2. Signal breakdown Conservative signals: * +1 Integrity impact plausible: dirty writeback cache mappings may be loaded into passthrough mode, which can cause data loss or filesystem inconsistency. * +1 Availability impact realistic: corrupted or lost storage data can make the affected volume or filesystem unusable. * +1 Important filesystem/storage path: dm-cache is part of the block/storage stack and affects persistent data integrity. * +1 Practical failure path demonstrated: the commit includes a concrete preload plus resume sequence that can lead to dirty mappings entering passthrough mode. * +1 Broad storage-stack relevance: device-mapper and LVM are common storage-management components, even though dm-cache passthrough switching is configuration-dependent. * -2 Requires admin/CAP_SYS_ADMIN in typical deployments: dmsetup reload/resume and LVM table manipulation normally require privileged storage administration. Paranoid adjustment: * +1 Local delegated trigger: in environments where storage management is delegated to a reduced-privilege service, container root with device access, or automation account, the practical PR may be closer to PR:L than full host-root. * -1 Reduced privilege still required: even in the paranoid model, the attacker usually needs access to storage-management tooling or a privileged service path. No memory-corruption, UAF, OOB write, arbitrary write, page-cache corruption, LPE, or network-reachable signal is supported by this patch. ## 3. Reachability analysis The realistic trigger is local control-plane access to dm-cache table reload and resume operations. In normal deployments this requires root or CAP_SYS_ADMIN, because device-mapper table manipulation is not available to ordinary users. Namespaces and containers usually do not lower the requirement unless the container is privileged or has delegated access to device-mapper nodes and storage-management capabilities. The affected mode is not a default network-exposed path. It requires dm-cache, writeback cache state with dirty mappings, LVM or dmsetup table preload behavior, and switching into passthrough mode. ## 4. Severity interpretation This behaves like an actionable storage integrity bug rather than a generic kernel crash or memory-corruption vulnerability. The demonstrated impact is persistent data loss or filesystem inconsistency, which is more serious than an ordinary local Moderate DoS. It is not a strong Important candidate in the conservative model because triggering normally requires privileged storage administration and there is no evidence of privilege escalation, memory corruption, or remote reachability. The paranoid score reaches Actionable Moderate because delegated storage-management environments can make the trigger more practical and the impact affects persistent data integrity. ## 5. One-sentence report phrase dm-cache could allow dirty writeback cache mappings to enter passthrough mode during LVM table preload and resume ordering, allowing a local storage-management actor to cause persistent data loss or filesystem inconsistency. ## 6. Manual review recommendation MANUAL CHECK RECOMMENDED Manual review is recommended because the issue has concrete persistent data-loss impact in an important storage path, even though it is not memory corruption and typically requires privileged local storage-management access. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: dm cache: fix dirty mapping checking in passthrough mode switching [ Upstream Commit: c2e86f647561fcf5e1c6eba7d75e9e0c4299c94d Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c2e86f647561fcf5e1c6eba7d75e9e0c4299c94d Changed files: drivers/md/dm-cache-metadata.c drivers/md/dm-cache-metadata.h drivers/md/dm-cache-target.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=c2e86f647561fcf5e1c6eba7d75e9e0c4299c94d ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-53061 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53061 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:H/A:L The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H The Best / paranoid CVSS score: 7.1 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: 3 Paranoid ActionableScore: 5 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 7.0 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).