From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-97433][MODERATE REGULAR] nvme: validate FDP configuration descriptor sizes [ Upstream Date: Thu, 24 Sep 2026 19:31:47 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-97433 X-AL-KERNEL-Priority: MODERATE REGULAR X-AL-KERNEL-Severity: MODERATE REGULAR X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 1 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: 97efd7a41aac08b43ea2337c5913a2bc75484f9f List-Id: CVE: CVE-2026-97433 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: nvme: validate FDP configuration descriptor sizes [ Upstream Commit: 97efd7a41aac08b43ea2337c5913a2bc75484f9f Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=97efd7a41aac08b43ea2337c5913a2bc75484f9f Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97433 Analysis date: Thu, 24 Sep 2026 19:31:47 -0400 ActionableScore: 1 ActionableScore lower bound: unknown 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-2026-97433 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97433 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 REGULAR 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-2026-97433 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-97433 CHECK WITH IMPACT FROM ORIG NN MODERATE 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-125;*CWE-835;*CWE-20;BEST CVSS score: '4.6';DESCR 'A malformed FDP configuration log from an NVMe controller can contain a zero or oversized descriptor size. The host parser can then loop without progress or access data beyond the received log buffer while walking configuration descriptors. For the CVSS the PR:N because the triggering input is supplied by the NVMe controller and no local account on the affected host is required after a malicious or faulty device is connected. The attack vector is AV:P because reliable exploitation requires physical control of an NVMe device or an equivalent ability to provide a malicious virtual controller. Impact is denial of service through CPU exhaustion or a host kernel crash. The patch context does not demonstrate a write primitive, use after free, information disclosure path, or plausible privilege escalation.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1) YES NVME LOG LINUS NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=1 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=NO NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=NO ManualReview=RECOMMENDED AutoDowngradeAllowed=YES 1. ActionableScore * Raw conservative score: 1 * Conservative score: 1 * Raw paranoid score: 1 * Paranoid score: 1 * Final recommended bucket: **Ordinary Moderate**:: The score reflects a controller supplied malformed log that can cause an unbounded parser loop or an invalid host kernel read. No score floor applies because there is no UAF, write primitive, authorization bypass, ownership violation, or demonstrated attacker controlled reuse. 2. Signal breakdown * +1 Firmware mediated external influence. The FDP configuration log is supplied by the NVMe controller and descriptor size is parsed from controller controlled data. * +1 Reliable kernel DoS. A zero descriptor size can prevent parser progress and an oversized descriptor can cause parsing beyond the received log buffer. The stated effects support CPU exhaustion or a kernel fault. * -1 Corruption is highly constrained. The patch establishes only malformed size handling and an out of bounds read or loop. It does not establish an out of bounds write, active object corruption, or a user visible data disclosure path. Important non-awarded signals: * Controlled reclaim is not demonstrated. * Arbitrary or directed kernel write is not demonstrated. * RealUAF is not established. * Confidentiality is not awarded because no bytes are shown to be copied back to userspace, network peers, or the controller. * Integrity is not awarded because the parser does not write through the malformed descriptor. * Remote network reachability is not established. The input is received from a local NVMe controller or equivalent virtual controller. * Privilege escalation is not supported by the patch context. * No extra Availability point is awarded because CPU exhaustion and a possible kernel fault are alternative consequences of the same parser defect. 3. Reachability analysis The vulnerable parser consumes an FDP configuration log returned by an NVMe controller. A malicious or faulty physical NVMe device can supply a zero or oversized dsze field. An equivalent scenario may exist where an attacker can provide a malicious virtual NVMe controller, but the supplied patch does not establish a complete unprivileged virtual-device attack chain. Host-admin-equivalent privilege is not required after an attacker can provide the malformed controller response. Therefore HostAdminRequired is NO. This does not mean that ordinary local users can attach or emulate an NVMe controller. No namespace scoped capability path is established, so NamespaceScopedPrivilege is UNKNOWN. The relevant prerequisite is control of device firmware, physical device attachment, or a controller-emulation layer. No race is involved. The malformed FDP log is processed deterministically when the host queries FDP granularity. 4. Primitive and severity interpretation The exact primitive is unchecked descriptor-size arithmetic while walking the controller supplied FDP configuration log. Before the fix, dsze equal to zero could leave the parser at the same descriptor, while an oversized dsze could advance the parser beyond the validated log boundary. This is not a lifetime defect. No freed object is referenced, no refcount is mutated after object destruction, and no stale structured object is consumed. It is therefore not a Class A or Class B corruption issue. PrimitiveClass is CLASS_C because the demonstrated effect is invalid parser state leading to a loop, invalid read, warning, or host DoS. The practical consequence is controller induced CPU consumption or a possible kernel crash. A stronger consequence such as information disclosure, memory corruption, host privilege escalation, or guest to host escape is speculative and unsupported by the supplied patch. ImportantCandidate is NO and AutoDowngradeAllowed is YES because the established primitive is constrained and crash or DoS oriented. 5. One-sentence report phrase A malformed FDP configuration descriptor from an NVMe controller can use a zero or oversized dsze value to cause non progressing parser iteration or an out of bounds host kernel read, resulting in a possible denial of service. 6. Manual review recommendation MANUAL CHECK RECOMMENDED Confirm whether the target environment permits untrusted physical NVMe devices, hot plug storage, passthrough devices, or attacker controlled virtual NVMe controllers. If none apply, practical exposure is limited. 7. Call-site confidence Call-site confidence: medium ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: nvme: validate FDP configuration descriptor sizes [ Upstream Commit: 97efd7a41aac08b43ea2337c5913a2bc75484f9f Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=97efd7a41aac08b43ea2337c5913a2bc75484f9f Changed files: drivers/nvme/host/core.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=97efd7a41aac08b43ea2337c5913a2bc75484f9f ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-97433 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97433 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: Not available 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: 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: MODERATE KPANIC detected for this report: NO Published priority for this report (same as in Subject): MODERATE REGULAR 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).