From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-72467][LOW] xprtrdma: Check frwr_wp_create() during connect [ Upstream Date: Sat, 15 Aug 2026 02:51:40 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-72467 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: unknown X-AL-KERNEL-Commit: 3b252fe1778b2cdd68283146455929801bc2abd7 List-Id: CVE: CVE-2026-72467 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: xprtrdma: Check frwr_wp_create() during connect [ Upstream Commit: 3b252fe1778b2cdd68283146455929801bc2abd7 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3b252fe1778b2cdd68283146455929801bc2abd7 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72467 Analysis date: Sat, 15 Aug 2026 02:51:40 -0400 ActionableScore: 1 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate / Low-like Manual review required: NO Summary: No one-sentence report phrase was found. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72467 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72467 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-2026-72467 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-252;**CWE-476;CWE-754;BEST CVSS score: '4.7';DESCR 'An unchecked frwr_wp_create() failure in the xprtrdma connect path can leave the client transport marked connected while the write-pad MR pointer is NULL. A later NFS/RDMA read with a non-4-byte-aligned receive length can reach rpcrdma_encode_write_list() and dereference that NULL MR through encode_rdma_segment(), causing a kernel crash. For the CVSS the PR:L is used for the paranoid score because a local unprivileged process that can access an existing NFS/RDMA mount may trigger reads and reconnect activity, while the required local MR allocation, DMA map, MR map, or post-send failure makes the attack high complexity. The issue is not directly network reachable. A remote NFS/RDMA peer alone is not expected to trigger the fault because the critical failure is local to the client. Impact is denial of service only, with no supported UAF, OOB access, information leak, or privilege escalation primitive.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 1) YES REMOTE NETWORK LOWERED_FROM_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 NO NO guess ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=1 1. ActionableScore * Conservative score: 1 * Paranoid score: 2 * Final recommended bucket: **Ordinary Moderate / Low-like**:: 2. Signal breakdown * Local unprivileged trigger: +1. A local process that can access an existing NFS/RDMA mount may trigger reads and reconnect activity. * Reliable kernel crash / strong DoS: +1. If the NULL write-pad MR state is reached, a later unaligned NFS/RDMA read can dereference NULL and crash the kernel. * Hard or unreliable race / special condition required: -1. The trigger depends on a local MR allocation, DMA-map, MR-map, or post-send failure during connect or reconnect. * Rare AND difficult-to-reach subsystem/configuration: -1. NFS/RDMA requires RDMA-capable deployment and is not a broad default client path. * Paranoid addition: +1 availability/exposure concern because the failure can crash the client kernel once the bad connected state is published. 3. Reachability analysis The bug is local to an NFS/RDMA client. A remote peer alone cannot force the local MR setup failure according to the commit message. A local user may trigger NFS/RDMA reads on an already mounted filesystem, but creating the mount or controlling RDMA setup is typically administrative. Namespaces do not meaningfully lower this unless an environment delegates access to an existing NFS/RDMA mount. The path is not default-enabled on ordinary systems and requires NFS over RDMA plus a local connect/reconnect failure. 4. Severity interpretation This behaves like an ordinary Moderate or Low-like kernel DoS issue rather than an Important vulnerability. The demonstrated primitive is NULL pointer dereference, not UAF, OOB write, refcount misuse, stale callback, arbitrary write, or page-cache corruption. Realistic exploitation evidence supports kernel crash only, with high complexity due to the required local MR setup failure. 5. One-sentence report phrase Unchecked frwr_wp_create() failure can leave an NFS/RDMA client transport connected with a NULL write-pad MR, allowing a later local unaligned read path to crash the kernel under specific reconnect failure conditions. 6. Manual review recommendation NO MANUAL CHECK NEEDED. The issue is DoS-only, non-network-triggerable by the peer alone, configuration-dependent, and lacks a supported memory corruption or privilege escalation primitive. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: xprtrdma: Check frwr_wp_create() during connect [ Upstream Commit: 3b252fe1778b2cdd68283146455929801bc2abd7 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3b252fe1778b2cdd68283146455929801bc2abd7 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=3b252fe1778b2cdd68283146455929801bc2abd7 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72467 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72467 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: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: 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).