From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-46023][MODERATE 7.0] dm mirror: fix integer overflow in create_dirty_log() Date: Wed, 27 May 2026 12:44:45 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-46023 X-AL-KERNEL-Priority: MODERATE 7.0 X-AL-KERNEL-Severity: MODERATE 7.0 X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: YES X-AL-KERNEL-ActionableScore: 5 X-AL-KERNEL-ActionableScore-Lower: 4 X-AL-KERNEL-Commit: 35f6b3281efd44d19110574663bc17a610bc73b9 List-Id: CVE: CVE-2026-46023 Priority: MODERATE 7.0 AL-KERNEL base severity: MODERATE KPANIC flag: YES Patch: dm mirror: fix integer overflow in create_dirty_log() Commit: 35f6b3281efd44d19110574663bc17a610bc73b9 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=35f6b3281efd44d19110574663bc17a610bc73b9 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46023 Analysis date: Wed, 27 May 2026 12:44:45 -0400 ActionableScore: 5 ActionableScore lower bound: 4 Actionable bucket: Actionable Moderate at minimum Manual review required: YES Summary: A crafted dm mirror table can overflow the dirty-log argument count and bypass bounds validation, leading to out-of-bounds argv reads and potential local kernel DoS. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-46023 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46023 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: YES A detailed explanation of the methodology and priority rules is included at the end of this message. ====================================================================== AL-KERNEL CLASSIFICATION RESULT ====================================================================== CVE-2026-46023 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:L/I:L/A:H';CWE-190;CWE-125;*CWE-20;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '6.6';DESCR 'A local integer overflow in dm mirror create_dirty_log() can make 2 plus param_count wrap before the argc bounds check. A crafted device mapper table can then pass an oversized param_count to dm_dirty_log_create(), causing out of bounds reads on the argv array. For the CVSS the PR:L is used only in the paranoid score where storage management is delegated to a reduced privilege service, privileged container, or local management role. The typical host case is closer to PR:H because loading device mapper tables normally requires CAP_SYS_ADMIN. The issue is not network reachable and does not involve UAF, out of bounds write, arbitrary write, or a demonstrated privilege escalation primitive. Impact is at least denial of service via invalid argv reads or kernel crash, with limited confidentiality or integrity concern only from parser state confusion.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 5) YES OOB DISK SIMPLEFIX HARDWARE LINUS KPANIC INCREASED_TO_MODERATE7_FROM_MODERATE_BASED_ON_GUESSCVSS NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=5 ActionableScoreLower=4 ## 1. ActionableScore * Conservative score: 4 * Paranoid score: 5 * Final recommended bucket: **Actionable Moderate at minimum**:: ## 2. Signal breakdown * Local delegated trigger: +1 Typical triggering requires CAP_SYS_ADMIN to load a device mapper table, but delegated storage management, privileged containers, or service accounts can lower this to a practical PR:L case. * Weak memory corruption / OOB read candidate: +1 The integer overflow can bypass argc validation and pass an oversized param_count to dm_dirty_log_create(), causing out-of-bounds reads from the argv array. * Reliable kernel crash / strong DoS: +1 Invalid argv reads can plausibly crash the kernel or destabilize the DM target setup path. * Important filesystem/storage path: +1 Device mapper mirror is a storage stack component and malformed table parsing can affect block device setup. * Availability impact realistic: +1 The primary impact is local DoS via invalid argument parsing or kernel fault. Conservative lowering factor: * Requires CAP_SYS_ADMIN in typical deployments: -1 to -2 practical reduction Ordinary hosts require privileged DM table loading, so the conservative score is lower than the delegated-storage paranoid case. No UAF, OOB write, arbitrary write, page-cache corruption, information disclosure, or demonstrated privilege escalation primitive is shown. ## 3. Reachability analysis The bug is local and reached through the device mapper table parser for dm mirror. A crafted table string with param_count near UINT_MAX can trigger the overflow. In normal deployments, loading DM tables requires CAP_SYS_ADMIN, so this is usually privileged. In cloud, container, appliance, or storage-service environments where DM setup is delegated, a less privileged local actor may reach it. It is not network reachable by itself. ## 4. Severity interpretation This behaves as an actionable Moderate issue, not an Important memory-corruption issue. The concrete primitive is an integer overflow leading to OOB reads of argv entries, with likely DoS. Theoretical confidentiality or integrity impact is limited and indirect because the patch does not show a read-back channel, controlled write, UAF, or arbitrary pointer overwrite. ## 5. One-sentence report phrase A crafted dm mirror table can overflow the dirty-log argument count and bypass bounds validation, leading to out-of-bounds argv reads and potential local kernel DoS. ## 6. Manual review recommendation MANUAL CHECK REQUIRED Reason: the bug is in a storage table parser and includes an OOB read condition. Practical urgency depends on whether DM table loading is restricted to full host root or delegated to less trusted storage/container workflows. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: dm mirror: fix integer overflow in create_dirty_log() Commit: 35f6b3281efd44d19110574663bc17a610bc73b9 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=35f6b3281efd44d19110574663bc17a610bc73b9 Commit description: The argument count calculation in create_dirty_log() performs `*args_used = 2 + param_count` before validating against argc. When a user provides a param_count close to UINT_MAX via the device mapper table string, this unsigned addition wraps around to a small value, causing the subsequent `argc < *args_used` check to be bypassed. The overflowed param_count is then passed as argc to dm_dirty_log_create(), where it can cause out-of-bounds reads on the argv array. Fix by comparing param_count against argc - 2 before performing the addition, following the same pattern used by parse_features() in the same file. Since argc >= 2 is already guaranteed, the subtraction is safe. Fixes: 1da177e ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Reported-by: Yuhao Jiang Signed-off-by: Junrui Luo Reviewed-by: Benjamin Marzinski Signed-off-by: Mikulas Patocka Signed-off-by: Greg Kroah-Hartman Changed files: drivers/md/dm-raid1.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=35f6b3281efd44d19110574663bc17a610bc73b9 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-46023 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46023 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:L/UI:N/S:U/C:L/I:L/A:H The Best / paranoid CVSS score: 6.6 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: 4 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: YES 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).