From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-72468][LOW] xprtrdma: Initialize re_id before removal registration [ Upstream Date: Sat, 15 Aug 2026 07:53:12 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-72468 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: 51248d877bbc6e604e38aeaf776c2781cb4f0dbd List-Id: CVE: CVE-2026-72468 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: xprtrdma: Initialize re_id before removal registration [ Upstream Commit: 51248d877bbc6e604e38aeaf776c2781cb4f0dbd Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=51248d877bbc6e604e38aeaf776c2781cb4f0dbd Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72468 Analysis date: Sat, 15 Aug 2026 07:53:12 -0400 ActionableScore: 0 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate / Low-like Manual review required: NO Summary: A race in xprtrdma can allow RDMA device removal to observe a newly registered removal notifier before ep re_id is initialized, causing a NULL rdma_cm_id dereference in the removal tracepoint and a local privileged kernel crash. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72468 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72468 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-2026-72468 LOW CHECK WITH IMPACT FROM ORIG NN IMPORTANT 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-362;CWE-367;**CWE-476;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '4.7';DESCR 'A race in xprtrdma can occur because ep re_id is assigned only after the RDMA removal notifier is registered. A local actor can race an NFS/RDMA mount against RDMA device removal so rpcrdma_ep_removal_done may call trace_xprtrdma_device_removal with a NULL rdma_cm_id. When the removal tracepoint is evaluated it dereferences id device name and copies route address data, which can trigger a NULL pointer dereference and crash the kernel. For the CVSS the PR:L is used for the paranoid score because some deployments may delegate mount or RDMA management capabilities to a reduced capability root, container root, or service account. The issue is not network reachable as packet traffic alone does not trigger it. Impact is denial of service only because the patch context supports a NULL dereference race, not UAF, OOB access, or an arbitrary write primitive.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 0) YES REMOTE DANGER NULLPTR RACE ERRORPATH UAF NETWORK KERNEL_PANIC_PLUS_UAF HARDWARE LOWERED_FROM_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 YES NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=0 ## 1. ActionableScore * Conservative score: 0 * Paranoid score: 0 * Final recommended bucket: **Ordinary Moderate / Low-like** ## 2. Signal breakdown Triggered signals: * Reliable kernel crash / strong DoS: +1 The race can pass NULL as rdma_cm_id to trace_xprtrdma_device_removal(), causing a NULL pointer dereference and kernel crash. Negative signals: * Hard or unreliable race / special timing required: -1 Triggering requires racing NFS/RDMA mount creation against RDMA device removal in a narrow initialization window. * Requires admin/root/CAP_* in typical deployments: -2 NFS/RDMA mount and RDMA device removal are normally administrator-controlled operations. * Rare AND difficult-to-reach subsystem/configuration: -1 NFS over RDMA requires RDMA hardware/configuration and is not a default/common path on most systems. Not awarded: * No remote/network-triggerable score. Packet traffic alone does not trigger this path. * No generic memory corruption score. The supported primitive is NULL dereference, not UAF, OOB write, double free, or type confusion. * No privilege escalation score. The patch does not show attacker-controlled reclaim, overwrite, stale callback control, or object confusion. * No confidentiality or integrity impact. The crash path is a NULL dereference in a tracepoint. ## 3. Reachability analysis The realistic trigger is a local administrator racing an NFS/RDMA mount against RDMA device removal. In normal deployments this requires host-level administrative control over mounts and RDMA device management. A paranoid interpretation may consider reduced-capability root, service accounts, or delegated management environments, but the attacker still needs local control-plane access rather than ordinary network reachability. The affected path is not broadly default-enabled and depends on NFS/RDMA plus RDMA device removal timing. Call-site confidence: high. The commit message and diff directly describe the registration order, the stale NULL ep->re_id window, and the tracepoint dereference. ## 4. Severity interpretation This behaves like an ordinary Moderate / Low-like local privileged DoS. Theoretical severity is limited because the demonstrated failure is a NULL pointer dereference. There is no supported memory corruption primitive beyond the invalid NULL dereference, and no evidence of LPE, information disclosure, or integrity impact. ## 5. One-sentence report phrase A race in xprtrdma can allow RDMA device removal to observe a newly registered removal notifier before ep re_id is initialized, causing a NULL rdma_cm_id dereference in the removal tracepoint and a local privileged kernel crash. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED Reason: the bug is a local privileged race leading to NULL pointer dereference DoS only, with no supported UAF, overwrite, type confusion, privilege escalation, or network-triggerable path. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: xprtrdma: Initialize re_id before removal registration [ Upstream Commit: 51248d877bbc6e604e38aeaf776c2781cb4f0dbd Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=51248d877bbc6e604e38aeaf776c2781cb4f0dbd Changed files: net/sunrpc/xprtrdma/verbs.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=51248d877bbc6e604e38aeaf776c2781cb4f0dbd ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72468 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72468 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:H 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).