From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-46299][LOW] hfsplus: fix held lock freed on hfsplus_fill_super() [ Upstream Date: Mon, 08 Jun 2026 15:01:14 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-46299 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: 3ca80e3012c8be85b4f8d0d20eac8d3b17ff257e List-Id: CVE: CVE-2026-46299 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: hfsplus: fix held lock freed on hfsplus_fill_super() [ Upstream Commit: 3ca80e3012c8be85b4f8d0d20eac8d3b17ff257e Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3ca80e3012c8be85b4f8d0d20eac8d3b17ff257e Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46299 Analysis date: Mon, 08 Jun 2026 15:01:14 -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-2026-46299 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46299 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-2026-46299 LOW CHECK Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';CWE-667;*CWE-772;CWE-703;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.7';DESCR 'HFSPLUS mount error handling can free tree data while tree_lock is still held because hfsplus_fill_super() may jump to cleanup after hfsplus_cat_build_key() fails without releasing the search structure. This is primarily a local cleanup and locking bug in the mount path and the observed symptom is a held lock freed warning. For the CVSS the PR:L is used for the paranoid score because some deployments may delegate mount capability to a container root, automount service, or reduced privilege local account, while the typical base case requires administrative mount privileges. The issue is not network reachable and requires local interaction with an HFSPLUS filesystem image or mount operation. Impact is expected to be denial of service or diagnostic warning behavior rather than confidentiality or integrity compromise.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 0) MAYBE DISK INIT ERRORPATH UAF KERNEL_PANIC_PLUS_UAF HARDWARE LINUS 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: 1 * Final recommended bucket: **Ordinary Moderate / Low-like** 2. Signal breakdown * Requires admin/root/CAP_SYS_ADMIN in typical deployments: -2. Triggering requires mounting an HFSPLUS filesystem, which normally requires administrative mount privileges. * Hard or unreliable special condition required: -1. The demonstrated trigger required GDB manipulation of max_unistr_len to force the error path, so natural reachability from a crafted image is not clearly demonstrated. * Rare AND difficult-to-reach subsystem/configuration: -1. HFSPLUS is a niche filesystem and the vulnerable path is an uncommon mount error path. * Reliable kernel crash / strong DoS: +0 conservative. The observed result is a held lock freed warning under lockdep, not a demonstrated reliable panic on production kernels. * Paranoid local delegated trigger: +1. In environments where mount capability is delegated to container root, automount helpers, or reduced privilege services, the practical PR may be lower than full host root. 3. Reachability analysis The bug is triggered during hfsplus_fill_super() while mounting an HFSPLUS filesystem. In normal deployments, this requires CAP_SYS_ADMIN or equivalent control over mount operations and access to a block device or filesystem image. It is not network reachable. User namespaces or containerized environments may lower the practical privilege boundary if HFSPLUS mounting is delegated, but this is not the common default. The error path appears narrow and was confirmed by forcing an internal parameter with GDB, so realistic exploitation conditions are weak. 4. Severity interpretation This behaves like a low-end Moderate or Low-like cleanup/locking bug rather than an Important-class vulnerability. The patch fixes a missing hfs_find_exit() on an error path, preventing tree_lock from remaining held when the tree object is freed. There is no demonstrated UAF dereference, attacker-controlled overwrite, information leak, or privilege-escalation primitive. The theoretical risk is local DoS or diagnostic warning behavior, while realistic exploitation evidence is limited. 5. One-sentence report phrase An HFSPLUS mount error path can free tree data while tree_lock is still held, causing a held lock freed warning and possible local DoS under uncommon mount failure conditions. 6. Manual review recommendation NO MANUAL CHECK NEEDED. The issue requires privileged or delegated mount access, is not remotely reachable, shows no concrete memory corruption primitive beyond a lock cleanup bug, and the practical impact appears limited to warning or local availability degradation. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: hfsplus: fix held lock freed on hfsplus_fill_super() [ Upstream Commit: 3ca80e3012c8be85b4f8d0d20eac8d3b17ff257e Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3ca80e3012c8be85b4f8d0d20eac8d3b17ff257e Changed files: fs/hfsplus/super.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=3ca80e3012c8be85b4f8d0d20eac8d3b17ff257e ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-46299 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46299 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:L/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS score: 4.7 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).