From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-68418][LOW] RDMA/irdma: Prevent user-triggered null deref on QP create [ Upstream Date: Mon, 10 Aug 2026 20:28:21 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-68418 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: 2 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: ec675b4cdfd378d8c9dd8c93126c024f2469bd79 List-Id: CVE: CVE-2026-68418 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: RDMA/irdma: Prevent user-triggered null deref on QP create [ Upstream Commit: ec675b4cdfd378d8c9dd8c93126c024f2469bd79 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ec675b4cdfd378d8c9dd8c93126c024f2469bd79 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68418 Analysis date: Mon, 10 Aug 2026 20:28:21 -0400 ActionableScore: 2 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-2026-68418 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68418 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-2026-68418 LOW CHECK WITH IMPACT FROM ORIG NN LOW Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H';**CWE-476;*CWE-20;CWE-754;BEST CVSS score: '5.5';DESCR 'A NULL pointer dereference in the RDMA irdma user QP creation path can occur when a local userspace request sets user_wqe_bufs to 0 and leaves iwqp iwpbl uninitialized. The pointer is later used by the virtual QP setup path, which can crash the kernel and cause denial of service. For the CVSS the PR:L is used because triggering requires a local process with access to the RDMA userspace verbs device, typically /dev/infiniband/uverbs or an equivalent delegated RDMA device permission. The issue is not directly network reachable because it is triggered by local QP creation control plane operations rather than remote RDMA traffic. Impact is denial of service only, with no supported evidence of information disclosure, arbitrary write, UAF, or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2) YES LOCK NULLPTR SIMPLEFIX NETWORK HARDWARE DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=2 1. ActionableScore * Conservative score: 2 * Paranoid score: 2 * Final recommended bucket: **Ordinary Moderate / Low-like** 2. Signal breakdown * Local unprivileged trigger: +1. A local process with access to the RDMA userspace verbs interface can submit a QP create request with user_wqe_bufs set to 0. * Reliable kernel crash / strong DoS: +1. The commit explicitly states that iwqp->iwpbl is later unconditionally dereferenced in irdma_setup_virt_qp, producing a NULL pointer dereference. * Weak corruption only: +0. This is an invalid NULL pointer dereference, not UAF, OOB write, double free, type confusion, refcount abuse, or attacker-controlled memory corruption. * RDMA/device-object API bonus: +0. The patch shows object configuration misuse, but not attacker control over memory layout, lifetime, callback targets, DMA mappings, or page ownership. * Remote reachable: +0. The vulnerable path is local QP creation through uverbs, not remote RDMA packet processing. * Privilege escalation plausible: +0. No supported evidence of reclaim, overwrite, stale callback, arbitrary write, or object confusion. * Availability impact realistic: +0 additional. Crash impact is already counted as reliable DoS, and there is no separate persistent/system-wide data corruption signal. 3. Reachability analysis A local user or process can trigger this only if it has access to the affected irdma RDMA device through the userspace verbs interface, typically /dev/infiniband/uverbs*. This does not require network reachability to the RDMA fabric and is not triggered by remote packets alone. Container or namespace impact depends on whether the RDMA device is delegated into the container. If uverbs access is exposed to an untrusted container or service account, PR remains effectively local-low rather than full administrator. The path is not broadly default-exposed on ordinary systems because it requires affected Intel RDMA hardware and userspace RDMA device access. Call-site confidence: high. The commit directly identifies the later unconditional dereference in irdma_setup_virt_qp and the patch changes the QP setup path to reject the missing PBL before that dereference. 4. Severity interpretation This behaves like an ordinary Moderate local DoS rather than an Important-class vulnerability. The theoretical bug class is pointer misuse, but the demonstrated primitive is only a NULL pointer dereference. There is no evidence of memory reuse, controlled overwrite, information disclosure, integrity impact, privilege escalation, or cross-boundary security bypass. It should not be treated as an Actionable Moderate or Important candidate unless additional evidence shows a stronger primitive. 5. One-sentence report phrase A local user with access to the irdma RDMA uverbs device can create a QP with user_wqe_bufs set to 0, leaving iwqp->iwpbl NULL and triggering a kernel NULL pointer dereference during virtual QP setup, causing denial of service only. 6. Manual review recommendation NO MANUAL CHECK NEEDED. The issue is a clearly described local NULL dereference with DoS-only impact and no supported memory corruption or privilege escalation primitive. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: RDMA/irdma: Prevent user-triggered null deref on QP create [ Upstream Commit: ec675b4cdfd378d8c9dd8c93126c024f2469bd79 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ec675b4cdfd378d8c9dd8c93126c024f2469bd79 Changed files: drivers/infiniband/hw/irdma/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=ec675b4cdfd378d8c9dd8c93126c024f2469bd79 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68418 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68418 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:L/PR:L/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS score: 5.5 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: unknown Paranoid ActionableScore: 2 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).