From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-80813][MODERATE 7.0] nvmet: fix NULL pointer dereference in nvmet_execute_identify_nslist() Date: Fri, 04 Sep 2026 14:24:19 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-80813 X-AL-KERNEL-Priority: MODERATE 7.0 X-AL-KERNEL-Severity: MODERATE 7.0 X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: YES X-AL-KERNEL-ActionableScore: 5 X-AL-KERNEL-ActionableScore-Lower: 4 X-AL-KERNEL-Commit: 61dc1a37e04d4003a19095f54883358330034a39 List-Id: CVE: CVE-2026-80813 Priority: MODERATE 7.0 AL-KERNEL base severity: MODERATE KPANIC flag: YES Patch: nvmet: fix NULL pointer dereference in nvmet_execute_identify_nslist() Commit: 61dc1a37e04d4003a19095f54883358330034a39 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=61dc1a37e04d4003a19095f54883358330034a39 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80813 Analysis date: Fri, 04 Sep 2026 14:24:19 -0400 ActionableScore: 5 ActionableScore lower bound: 4 Actionable bucket: Actionable Moderate at minimum Manual review required: YES Summary: A remote NVMe host with access to the target endpoint can trigger a NULL pointer dereference in nvmet_execute_identify_nslist through an Identify CNS 07h command, causing a kernel crash and denial of service without evidence of privilege escalation. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-80813 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80813 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 7.0 Manual review required: YES A detailed explanation of the methodology and priority rules is included at the end of this message. ====================================================================== AL-KERNEL CLASSIFICATION RESULT ====================================================================== CVE-2026-80813 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-80813 CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H';**CWE-476;*CWE-20;CWE-754;BEST CVSS score: '6.5';DESCR 'A NULL pointer dereference in the NVMe target Identify namespace list path occurs because nvmet_execute_identify_nslist can use req ns csi even though this handler does not initialize req ns. A remote NVMe host can trigger this with an Identify command using CNS 07h for Active Namespace ID List for a specific I/O Command Set when an enabled namespace with a larger NSID is present. For the CVSS the PR:N is used because the attacker does not need local privileges on the target, only reachability to the exposed NVMe target endpoint. The issue is network reachable in NVMe over Fabrics deployments, but it is best modeled as AV:A because NVMe targets are usually deployed on isolated storage or data center networks rather than the public Internet. Impact is denial of service via kernel oops or crash. No direct evidence of information disclosure or privilege escalation is supported by the shown code path.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 5) YES DANGER NULLPTR SIMPLEFIX NVME LINUS TEST KPANIC INCREASED_TO_MODERATE7_FROM_MODERATE_BASED_ON_GUESSCVSS YES NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=5 ActionableScoreLower=4 ## 1. ActionableScore * Conservative score: 4 * Paranoid score: 5 * Final recommended bucket: **Actionable Moderate at minimum**:: ## 2. Signal breakdown * Remote reachable / network-triggerable: +2 The affected code is in the NVMe target command handling path and can be reached by a remote NVMe host that can connect to the exposed target endpoint. * Reliable kernel crash / strong DoS: +1 The bug is a direct NULL pointer dereference of req->ns->csi when req->ns is always NULL in this handler. The described condition leads to an oops or crash. * Important filesystem/storage path: +1 The issue affects NVMe target admin command handling, which is a storage control path and can impact availability of a storage server. * Availability impact realistic: +1 in paranoid score only Once the NVMe target is reachable and an enabled namespace with a larger NSID exists, the trigger appears straightforward and can cause a kernel crash. This makes the DoS operationally meaningful. No memory corruption, UAF, OOB write, arbitrary write, page-cache corruption, or privilege escalation primitive is shown. This is best treated as NULL dereference DoS, not LPE. ## 3. Reachability analysis A remote NVMe host can trigger the bug by issuing an Identify command with CNS 07h when match_css is set and a suitable enabled namespace exists. The attacker does not need local code execution on the target host, only protocol reachability to the NVMe target endpoint. This is network reachable in NVMe over Fabrics deployments, but the exposure is usually adjacent or internal rather than Internet-wide. NVMe/TCP and similar targets are typically deployed in storage or data-center networks. Containers and namespaces do not significantly reduce the requirement unless they provide access to the storage network or target endpoint. The path is not enabled on ordinary systems by default. It requires an NVMe target configuration with exposed namespaces. ## 4. Severity interpretation This behaves like an actionable Moderate issue rather than ordinary Low because it is remotely reachable from a storage client and can crash the kernel. It does not reach Important based on the supplied patch because the primitive is a NULL pointer dereference only. Theoretical impact beyond DoS is not supported. There is no evidence of attacker-controlled reclaim, stale object reuse, writable corruption, type confusion, information disclosure, or privilege escalation. ## 5. One-sentence report phrase A remote NVMe host with access to the target endpoint can trigger a NULL pointer dereference in nvmet_execute_identify_nslist through an Identify CNS 07h command, causing a kernel crash and denial of service without evidence of privilege escalation. ## 6. Manual review recommendation MANUAL CHECK REQUIRED. YES REQUIRES MANUAL CHECK. Reason: the bug is network reachable in NVMe target deployments and can cause a reliable kernel crash, even though the demonstrated primitive is only NULL pointer dereference DoS. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: nvmet: fix NULL pointer dereference in nvmet_execute_identify_nslist() Commit: 61dc1a37e04d4003a19095f54883358330034a39 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=61dc1a37e04d4003a19095f54883358330034a39 Commit description: When a host issues an Identify command with CNS 07h (Active Namespace ID List for a specific I/O Command Set), nvmet_execute_identify_nslist() is called with match_css set. The command-set filter dereferences req->ns, but this handler never calls nvmet_req_find_ns(), so req->ns is always NULL (nvmet_req_init() resets it to NULL). As soon as an enabled namespace with an NSID greater than the requested value exists, req->ns->csi dereferences a NULL pointer and oopses. Besides the crash, the comparison is logically wrong: to filter the list by command set it must test the command set of the namespace being iterated, not a single fixed value. Use the loop variable ns->csi. Fixes: 61c9967 ("nvmet: implement active command set ns list") Signed-off-by: Guixin Liu Reviewed-by: Hannes Reinecke Reviewed-by: Christoph Hellwig Reviewed-by: Nilay Shroff Signed-off-by: Keith Busch Signed-off-by: Greg Kroah-Hartman Changed files: drivers/nvme/target/admin-cmd.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=61dc1a37e04d4003a19095f54883358330034a39 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-80813 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80813 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:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS score: 6.5 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: 4 Paranoid ActionableScore: 5 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: YES Published priority for this report (same as in Subject): MODERATE 7.0 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).