From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-46284][LOW] mm/hugetlb: fix early boot crash on parameters without '=' separator Date: Mon, 08 Jun 2026 15:46:24 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-46284 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: 2774bcf714739cc6bb86f8812167bb9fbda70f6a List-Id: CVE: CVE-2026-46284 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: mm/hugetlb: fix early boot crash on parameters without '=' separator Commit: 2774bcf714739cc6bb86f8812167bb9fbda70f6a Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2774bcf714739cc6bb86f8812167bb9fbda70f6a Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46284 Analysis date: Mon, 08 Jun 2026 15:46:24 -0400 ActionableScore: 0 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate / Low-like Manual review required: NO Summary: No one-sentence report phrase was found. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-46284 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46284 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-2026-46284 LOW CHECK Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H';**CWE-476;*CWE-20;CWE-754;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '4.6';DESCR 'A NULL pointer dereference can occur during early boot when hugepages, hugepagesz, or default_hugepagesz is present on the kernel command line without an equals separator. The early parameter parser may pass a NULL value to hugetlb_add_param(), which then reaches strlen() and can crash the system before normal boot completes. For the CVSS the PR:N in the paranoid physical access interpretation because a person with bootloader or console control may not need an OS account to supply the malformed kernel parameter. In the more typical operational scenario, triggering requires administrative control over the kernel command line and a reboot. The issue is not network reachable. Impact is denial of service only through boot failure, with no supported path to information disclosure, memory corruption, or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 0) SKIP CVE-2026-46284 SKIP The Fixes patch not applied yet, so unlikely that actual: 5b47c02967ab770aa7661c8863a21b2fd59e35ff YES NO NO unknown MAYBE INIT SIMPLEFIX LINUS MEMORY DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=0 1. ActionableScore * Conservative score: 0 * Paranoid score: 0 * Final recommended bucket: **Ordinary Moderate / Low-like** 2. Signal breakdown * Reliable kernel crash / strong DoS: +1. A malformed early boot parameter can cause a NULL pointer dereference in strlen() and stop the system during boot. * Availability impact realistic: +1. The impact is a boot failure, which is system-wide until the kernel command line is corrected. * Requires admin/root/boot configuration control in typical deployments: -2. Triggering normally requires modifying the kernel command line and rebooting. * Physical-only interpretation does not increase score. If triggered through bootloader or console access, this is still a physical or boot-control scenario, not a remotely reachable vulnerability. * No memory corruption score. The primitive is NULL dereference only, with no UAF, OOB write, overwrite target, or reclaim primitive. * No confidentiality or integrity score. There is no supported disclosure, write primitive, policy bypass, or privilege escalation path. 3. Reachability analysis The bug is triggered by specifying hugepages, hugepagesz, or default_hugepagesz on the kernel command line without an equals separator. In normal deployments, only an administrator, boot manager, provisioning system, or someone with console or bootloader control can supply this input. Namespaces and containers do not materially lower the privilege requirement because the affected parser runs during early boot before containers exist. The path is not network reachable and is not reachable by ordinary local users after boot. 4. Severity interpretation This behaves like a Low-like or ordinary Moderate availability issue, not an actionable Moderate or Important kernel vulnerability. The theoretical impact is a reliable early boot crash, but the realistic exploitation condition is control over boot parameters. There is no evidence of memory corruption beyond a NULL dereference, and no plausible privilege escalation or sensitive data access primitive is supported by the patch. 5. One-sentence report phrase A malformed hugetlb kernel command line parameter without an equals separator can cause an early boot NULL pointer dereference and prevent the system from booting, but triggering requires boot parameter control and has DoS-only impact. 6. Manual review recommendation NO MANUAL CHECK NEEDED. This can be auto-closed for urgent triage purposes because it is a boot-parameter-only NULL dereference with no network path, no local unprivileged trigger, and no memory corruption or privilege escalation primitive. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: mm/hugetlb: fix early boot crash on parameters without '=' separator Commit: 2774bcf714739cc6bb86f8812167bb9fbda70f6a Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2774bcf714739cc6bb86f8812167bb9fbda70f6a Commit description: If hugepages, hugepagesz, or default_hugepagesz are specified on the kernel command line without the '=' separator, early parameter parsing passes NULL to hugetlb_add_param(), which dereferences it in strlen() and can crash the system during early boot. Reject NULL values in hugetlb_add_param() and return -EINVAL instead. Link: https://lore.kernel.org/20260409105437.108686-4-thorsten.blum@linux.dev Fixes: 5b47c02 ("mm/hugetlb: convert cmdline parameters from setup to early") Signed-off-by: Thorsten Blum Reviewed-by: Muchun Song Cc: David Hildenbrand Cc: Frank van der Linden Cc: Oscar Salvador Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman Changed files: mm/hugetlb.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=2774bcf714739cc6bb86f8812167bb9fbda70f6a ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-46284 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46284 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:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS score: 4.6 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: 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).