From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-93230][LOW] mm/hugetlb: initialize gigantic bootmem hugepage struct pages earlier [ Upstream Date: Thu, 24 Sep 2026 12:07:34 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-93230 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: 09505232eced5f1c42902d8f28740f070c3fc6dc List-Id: CVE: CVE-2026-93230 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: mm/hugetlb: initialize gigantic bootmem hugepage struct pages earlier [ Upstream Commit: 09505232eced5f1c42902d8f28740f070c3fc6dc Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=09505232eced5f1c42902d8f28740f070c3fc6dc Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93230 Analysis date: Thu, 24 Sep 2026 12:07:34 -0400 ActionableScore: 0 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate Manual review required: NO Summary: An initialization-order error can expose uninitialized gigantic HugeTLB struct pages during zone-contiguity evaluation, potentially producing incorrect allocator state or a configuration-dependent early boot panic. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-93230 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93230 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-2026-93230 LOW https://www.kernelcve.org/list/?q=CVE-2026-93230 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:N/I:N/A:H';CWE-665;*CWE-457;CWE-908;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.1';DESCR 'Gigantic bootmem HugeTLB struct pages can remain uninitialized when page_alloc_init_late evaluates pageblock and zone contiguity state. This can cause set_zone_contiguous to compute an incorrect result and can produce an early boot panic when poisoned page validation is present. No UAF, OOB access, stale pointer traversal, or attacker controlled memory corruption primitive is demonstrated. For the CVSS the PR:H value is used because reliable triggering requires administrative control over boot parameters and a special HugeTLB noinit or HVO configuration. The issue is not network reachable and cannot normally be triggered by an unprivileged local process after the system has booted. Realistic impact is limited availability degradation or incorrect allocator setup. The paranoid impact raises availability to high because an early boot panic is plausible, while confidentiality and integrity remain none.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 0) SKIP CVE-2026-93230 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: url YES NO NO unknown MAYBE READ INIT UAF IMPROVEONLY MEMORY DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=0 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=YES NamespaceScopedPrivilege=NO ImportantCandidate=NO ManualReview=NO AutoDowngradeAllowed=YES ## 1. ActionableScore * Raw conservative score: -3 * Conservative score: 0 * Raw paranoid score: -2 * Paranoid score: 0 * Applied conservative lower bound: -3 -> 0 * Applied paranoid lower bound: -2 -> 0 * Final recommended bucket: **Ordinary Moderate**:: ## 2. Signal breakdown Conservative signals: * -2 Full host-admin-equivalent privilege. Triggering requires global boot-time HugeTLB configuration that an ordinary user or namespace administrator cannot change. * -1 Rare and difficult-to-reach configuration. The path requires gigantic bootmem HugeTLB pages combined with the noinit or HVO initialization behavior. * +0 No concrete corruption primitive. The observed uninitialized state is used while computing zone contiguity, but no UAF, OOB access, invalid free, write primitive, or attacker-controlled target is established. * +0 No reliable crash point. The current behavior may calculate an incorrect zone-contiguity state. The described panic additionally depends on poisoned-page checks being added to this path. Paranoid signals: * +1 Potential early boot panic. With poisoned-page validation in this path, inspecting the uninitialized struct page can panic during boot. * -2 Host-admin-equivalent boot configuration remains required. * -1 The affected gigantic HugeTLB noinit or HVO configuration remains unusual and unavailable to an ordinary attacker. Not awarded: * No remote or local-unprivileged reachability. * No UAF, stale object, repeated release, refcount mutation, OOB access, or controlled memory corruption. * No confidentiality or integrity signal. * No additional availability point because the potential boot panic is the only concrete paranoid availability consequence. * No filesystem, authorization, namespace, COW, or security-boundary primitive. ## 3. Reachability analysis The vulnerable ordering occurs during global kernel initialization. Reaching it requires gigantic bootmem HugeTLB pages whose struct pages follow the noinit or HVO path. Establishing or changing the relevant boot configuration requires host-administrator control and a reboot. An ordinary local user cannot trigger the sequence after boot. Capabilities held in a user or network namespace do not control this global initialization, so the complete operation is not namespace-scoped. There is no network trigger, device-input dependency, or timing race. No special physical hardware is established, but the required boot configuration is uncommon and administratively controlled. ## 4. Primitive and severity interpretation The exact defect is an initialization-order error. `page_alloc_init_late()` can inspect gigantic HugeTLB `struct page` entries before `gather_bootmem_prealloc()` has initialized them. This can produce an incorrect zone-contiguity decision and, with additional poisoned-page checks, an early boot panic. This is CLASS_C invalid-state or DoS behavior. It is not a lifetime violation and does not establish an independently useful corruption primitive. The uninitialized pages are not shown being exposed to an attacker, reused after free, written out of bounds, or used to select an attacker-controlled address. The demonstrated practical consequence is incorrect allocator setup. The paranoid consequence is boot failure. Privilege escalation and confidentiality or integrity effects are unsupported. ImportantCandidate is therefore NO, and automatic downgrade is allowed. ## 5. One-sentence report phrase An initialization-order error can expose uninitialized gigantic HugeTLB struct pages during zone-contiguity evaluation, potentially producing incorrect allocator state or a configuration-dependent early boot panic. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED The issue requires host-controlled boot configuration and establishes neither attacker-reachable memory corruption nor a security-boundary primitive. ## 7. Call-site confidence Call-site confidence: high ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: mm/hugetlb: initialize gigantic bootmem hugepage struct pages earlier [ Upstream Commit: 09505232eced5f1c42902d8f28740f070c3fc6dc Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=09505232eced5f1c42902d8f28740f070c3fc6dc Changed files: include/linux/hugetlb.h mm/hugetlb.c mm/mm_init.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=09505232eced5f1c42902d8f28740f070c3fc6dc ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-93230 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93230 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:H/PR:H/UI:N/S:U/C:N/I:N/A:L The Best / paranoid CVSS vector: AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS score: 4.1 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: 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).