From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-98964][MODERATE REGULAR] nvmet: use the local P2P device on metadata allocation failure [ Upstream Date: Mon, 26 Oct 2026 14:56:15 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-98964 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: 3c231142c4f4bb96836469eb276026ec55940093 List-Id: CVE: CVE-2026-98964 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: nvmet: use the local P2P device on metadata allocation failure [ Upstream Commit: 3c231142c4f4bb96836469eb276026ec55940093 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3c231142c4f4bb96836469eb276026ec55940093 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98964 Analysis date: Mon, 26 Oct 2026 14:56:15 -0400 ActionableScore: 1 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate Manual review required: NO Summary: An NVMe target metadata-allocation failure can free a P2P data SGL using an uninitialized or stale PCI-device selector, plausibly crashing the kernel but without a confirmed UAF or memory-corruption primitive. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-98964 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98964 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-2026-98964 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-98964 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=1 LEGACY=MODERATE RESULT=DIFF (final Legacy and Aegis differ; FINAL: MODERATE, Aegis: MODERATE_KPANIC) Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H';CWE-763;**CWE-476;CWE-404;Other CVSS 'AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.9';DESCR 'An error path in nvmet_req_alloc_p2pmem_sgls can free an allocated data SGL through req p2p_dev before that field is assigned when the later metadata SGL allocation fails. This can pass a NULL or stale PCI device to PCI P2P memory cleanup and may cause a kernel crash. A stale valid device could also direct cleanup to the wrong P2P memory pool, but the patch does not establish an arbitrary write, UAF, or information disclosure primitive. For the CVSS the PR:N value reflects an NVMe initiator that can submit requests to an already reachable target lacking additional authorization. AV:A and AC:H reflect the required NVMe target reachability, PCI P2P configuration, metadata use, successful data allocation, and a specifically timed or induced metadata allocation failure. Automated impact decision path. The original SimpleNet classifier selected MODERATE. The primary LLM estimated paranoid CVSS 5.9 and the production ActionableScore returned 1 with recommendation Ordinary Moderate. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. No severity changing production threshold or specialist override was recorded. The legacy KP specialist has no review artifact for this run. The legacy FD or DH downgrade specialist has no review artifact for this run. Exact triggered rule markers were V41_INHERITED_KPANIC_PROMOTION_BLOCKED and MANUAL_REVIEW_REQUIRED. The independent weaker Aegis shadow evaluated CVSS 2.7 and ActionableScore 1 with primitive class CLASS_C and manual review REQUIRED. Its independently reconciled impact was MODERATE_KPANIC. The models disagreed but the aggregation rules retained the production result. The final reported impact is MODERATE.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1) MAYBE INIT SIMPLEFIX NVME HARDWARE LINUS V41_INHERITED_KPANIC_PROMOTION_BLOCKED MANUAL_REVIEW_REQUIRED - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=1 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=NO NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=NO ManualReview=RECOMMENDED AutoDowngradeAllowed=YES RequiresHostUID0=NO AuthorizationDecisionBypass=NO ProtectedResourceImpact=NONE B4PendingReview=NO B4PendingConfirmed=NO 1. ActionableScore * Raw base score: 1 (+1 unsafe cleanup object selection, +1 plausible kernel crash, -1 unusual preconfigured P2P-metadata path). * Conservative score: 1; no floor or cap applies. * Raw paranoid score: 1. * Paranoid score: 1; wrong-pool corruption remains possible but unproven and receives no additional point. * Final recommended bucket: **Ordinary Moderate**:: 2. Signal breakdown * +1 weak/indirect corruption candidate: after data-SGL allocation succeeds, metadata allocation failure passes the not-yet-assigned `req->p2p_dev` into `pci_p2pmem_free_sgl()`. * +1 reliable crash/DoS concern: a NULL or stale PCI-device argument can plausibly fault during cleanup. * -1 rare and difficult-to-reach configuration: the path requires an already configured NVMe target using PCI P2P memory and metadata SGLs, followed by the particular allocation-failure sequence. * No UAF, OOB write, repeated release of the same reference, arbitrary write, controlled target, disclosure, or authorization bypass is shown. * A stale valid device might select the wrong P2P pool, but actual allocator-state corruption and subsequent consumption are not established. Therefore NEW52/B5-R does not apply. * No additional availability point is awarded for the same possible crash. 3. Reachability analysis The supplied summary grounds a below-host-admin NVMe initiator that can submit requests to an already exposed target, so host UID 0 and effective host-admin power are not required for request submission. A host administrator must previously configure the target, PCI P2P path, and metadata use. Material attacker control over the metadata-allocation failure is limited: timing or induced memory pressure is suggested, not demonstrated as reliable. No namespace capability model or special race is established. 4. Primitive and severity reading The exact defect is use of an uninitialized or stale device selector during error cleanup, rather than a stale post-lifetime object use. The helper consumes that selector immediately while freeing the successfully allocated data SGL. The patch supports an invalid-device cleanup and plausible crash; wrong-pool bookkeeping damage is only a potential consequence because helper internals and later consumers are absent. This is CLASS_C, not a confirmed Class B corruption primitive. ImportantCandidate is therefore NO, while manual review remains recommended to inspect `pci_p2pmem_free_sgl()` behavior for NULL and mismatched-device inputs. 5. One-sentence report phrase An NVMe target metadata-allocation failure can free a P2P data SGL using an uninitialized or stale PCI-device selector, plausibly crashing the kernel but without a confirmed UAF or memory-corruption primitive. 6. Manual review advice MANUAL CHECK RECOMMENDED Confirm whether a mismatched non-NULL device can corrupt a P2P pool rather than merely fault. 7. Call-site confidence Call-site confidence: medium ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: nvmet: use the local P2P device on metadata allocation failure [ Upstream Commit: 3c231142c4f4bb96836469eb276026ec55940093 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3c231142c4f4bb96836469eb276026ec55940093 Changed files: drivers/nvme/target/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=3c231142c4f4bb96836469eb276026ec55940093 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-98964 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98964 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:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS vector: AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H The Best / paranoid CVSS score: 5.9 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).