From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-93048][LOW] mtd: part: reject MTDPART_OFS_RETAIN in mtd_add_partition() [ Upstream Date: Fri, 18 Sep 2026 01:44:45 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-93048 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: 1 X-AL-KERNEL-ActionableScore-Lower: 0 X-AL-KERNEL-Commit: 701c3ae7273e1adc20db5d97c42e0139b479f16b List-Id: CVE: CVE-2026-93048 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: mtd: part: reject MTDPART_OFS_RETAIN in mtd_add_partition() [ Upstream Commit: 701c3ae7273e1adc20db5d97c42e0139b479f16b Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=701c3ae7273e1adc20db5d97c42e0139b479f16b Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93048 Analysis date: Fri, 18 Sep 2026 01:44:45 -0400 ActionableScore: 1 ActionableScore lower bound: 0 Actionable bucket: Ordinary Moderate Manual review required: NO Summary: No one-sentence report phrase was found. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-93048 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93048 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-2026-93048 LOW https://www.kernelcve.org/list/?q=CVE-2026-93048 CHECK WITH IMPACT FROM ORIG NN LOW 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:N/A:H';*CWE-20;CWE-191;CWE-754;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.5';DESCR 'mtd_add_partition accepted the special MTDPART_OFS_RETAIN offset through the dynamic partition path even though that value only makes sense in the static partition table path. This can make the partition size calculation underflow and can lead to a WARN in add_mtd_device or to an invalid disabled empty partition being created after sanity checks. For the CVSS the PR:L is used only in the paranoid interpretation where a less privileged local service or delegated device management path can issue the BLKPG request. In the normal case PR:H is more realistic because changing MTD partitions requires administrative device control. The issue is not network reachable. Impact is mainly denial of service or invalid local storage partition state, with no clear evidence of information disclosure, arbitrary write, UAF, or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1) YES OOB HARDWARE DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=1 ActionableScoreLower=0 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=YES NamespaceScopedPrivilege=NO ImportantCandidate=NO ManualReview=NO AutoDowngradeAllowed=YES 1. ActionableScore * Raw conservative score: 0 * Conservative score: 0 * Raw paranoid score: 1 * Paranoid score: 1 * Final recommended bucket: **Ordinary Moderate**:: No floor or cap changed the score. 2. Signal breakdown Conservative signals: * +1: Invalid-state / validation bug. mtd_add_partition accepted MTDPART_OFS_RETAIN in a path that expects a direct offset, causing integer underflow and invalid partition handling. * +1: Device-management availability disruption. The described outcomes are WARN_ON in add_mtd_device or creation of a disabled empty partition. * -2: Host-admin-equivalent device partition management. BLKPG partition changes on NAND / MTD devices require administrative device control. Conservative total: 0. Paranoid signals: * +1: Invalid-state / validation bug. * +1: Device-management availability disruption. * +1: Paranoid availability interpretation. Repeated misuse or panic_on_warn-style deployments could make the WARN / invalid partition state more operationally disruptive. * -2: Host-admin-equivalent device partition management. Paranoid total: 1. Non-awarded signals: * No UAF, double free, stale pointer, OOB write, arbitrary write, or refcount corruption is established. * No confidentiality or integrity signal is awarded. * No remote reachability is established. * No security-boundary bypass is established. * WARN_ON alone is not treated as a reliable host-wide crash primitive. * Integer underflow is present, but the supplied behavior is caught by sanity checks or leads to invalid local partition state rather than a demonstrated memory corruption primitive. 3. Reachability analysis The trigger is local device control through BLKPG ioctl against NAND / MTD partition handling. This is an administrative storage-management operation, not ordinary unprivileged runtime access. HostAdminRequired=YES because the complete operation is partition manipulation on a device and is host-admin-equivalent in normal kernel semantics. NamespaceScopedPrivilege=NO because MTD / NAND partition management is not shown to be fully user-namespace or network-namespace scoped. No network trigger is present. No prior special race is required. Special hardware is limited to affected NAND / MTD devices, but this is not scored as rare hardware because the main reducing factor is administrative reachability. 4. Primitive and severity interpretation The exact primitive is invalid input acceptance of a special sentinel offset in a dynamic partition path, causing integer underflow and inconsistent local partition registration behavior. This is not an active-object UAF and not fixed stale storage. It is not a cleanup double-release case. There is no concrete repeated release or refcount mutation. PrimitiveClass=CLASS_C because the demonstrated effect is WARN / invalid state / possible local DoS behavior without an independently useful corruption primitive. ImportantCandidate=NO because there is no meaningful unresolved memory-corruption, authorization, ownership, or privilege-escalation primitive. AutoDowngradeAllowed=YES because automatic downgrade would not discard a concrete strong primitive. Likely operational severity is Low to ordinary Moderate. 5. One-sentence report phrase mtd_add_partition failed to reject MTDPART_OFS_RETAIN in the dynamic partition path, allowing an administrative BLKPG request to cause integer underflow and WARN or invalid disabled partition state without evidence of memory corruption or privilege escalation. 6. Manual review recommendation NO MANUAL CHECK NEEDED Reason: this is a host-admin-reachable validation bug with WARN / invalid partition state impact and no established UAF, arbitrary write, security-boundary bypass, or privilege-escalation primitive. 7. Call-site confidence Call-site confidence: high ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: mtd: part: reject MTDPART_OFS_RETAIN in mtd_add_partition() [ Upstream Commit: 701c3ae7273e1adc20db5d97c42e0139b479f16b Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=701c3ae7273e1adc20db5d97c42e0139b479f16b Changed files: drivers/mtd/mtdpart.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=701c3ae7273e1adc20db5d97c42e0139b479f16b ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-93048 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93048 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:L The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS score: 5.5 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: 0 Paranoid ActionableScore: 1 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).