From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-100075][MODERATE REGULAR] RDMA/srpt: Fix srpt_alloc_rw_ctxs() unwind counters [ Upstream Date: Fri, 25 Sep 2026 10:39:42 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-100075 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: 2 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: af00051dbc9f467d4840ec709680660a3f8990fa List-Id: CVE: CVE-2026-100075 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: RDMA/srpt: Fix srpt_alloc_rw_ctxs() unwind counters [ Upstream Commit: af00051dbc9f467d4840ec709680660a3f8990fa Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=af00051dbc9f467d4840ec709680660a3f8990fa Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-100075 Analysis date: Fri, 25 Sep 2026 10:39:42 -0400 ActionableScore: 2 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate Manual review required: NO Summary: No one-sentence report phrase was found. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-100075 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-100075 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-2026-100075 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-100075 CHECK WITH IMPACT FROM ORIG NN IMPORTANT Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';*CWE-672;*CWE-664;**CWE-400;BEST CVSS score: '4.8';DESCR 'A failure in srpt_alloc_rw_ctxs during multi buffer indirect descriptor setup can leave stale n_rw_ctx and n_rdma counters and a dangling rw_ctxs pointer in the I O context. Later send queue credit accounting can subtract an incorrect number of credits in srpt_queue_response or srpt_write_pending, potentially stalling I O processing or exhausting queue resources and causing denial of service. For the CVSS the PR:L value is used because an attacker normally needs access to the RDMA fabric and an SRP target session or an equivalent ability to submit SRPT requests. The attack vector is adjacent network because SRPT operates over RDMA fabrics and is not normally exposed to the public Internet. The failure path requires a multi buffer request and an allocation failure, so AC:H is appropriate. Impact is denial of service. A dangling pointer exists after the failed allocation, but the available patch context does not demonstrate a later dereference or a memory corruption primitive. YES REQUIRES MANUAL CHECK';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2) YES SIMPLEFIX NETWORK LINUS LOWERED_FROM_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=2 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=UNKNOWN NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=NO ManualReview=RECOMMENDED AutoDowngradeAllowed=YES 1. ActionableScore * Raw conservative score: 2 * Conservative score: 2 * Raw paranoid score: 2 * Paranoid score: 2 * Final recommended bucket: **Ordinary Moderate**:: 2. Signal breakdown * +1 Concrete invalid-state and resource-accounting defect. The error unwind frees `rw_ctxs` but preserves partially incremented `n_rw_ctx` and `n_rdma` values, so later SQ credit accounting uses state that no longer describes allocated RDMA contexts. * +1 Plausible availability impact. Incorrect send-queue credit subtraction can stall or disrupt SRPT I O request processing after the allocation failure path. Not awarded: * No Real UAF +2. `rw_ctxs` becomes dangling after `kfree`, but the supplied patch and commit do not establish a later dereference, traversal, write, or second free through that pointer. * No concrete repeated release or refcount mutation. There is one `kfree` operation, followed by pointer clearing. No exact same pointer is shown reaching another `kfree`, `put`, or refcount-changing operation. * No controlled reclaim, object replacement, arbitrary write, callback control, disclosure, integrity impact, or LPE primitive is demonstrated. * No direct remote reachability +2. SRPT uses RDMA fabric connectivity, but the complete attacker authentication, target-session, and request-submission prerequisites are not shown. * No reliable kernel crash +1. The supplied evidence establishes incorrect accounting and potential I O disruption, not an Oops or panic. * No hard-race penalty. This is an ordered allocation-failure unwind problem, not a demonstrated timing race. * No host-admin penalty. The evidence does not establish that host-admin-equivalent privilege is required for the complete trigger. 3. Reachability analysis The evaluated attacker is an RDMA/SRP initiator able to submit a multi-buffer indirect descriptor to an SRPT target. Reaching the vulnerable path also requires `srpt_alloc_rw_ctxs()` to fail partway through context allocation, which may depend on memory pressure or allocation conditions not shown in the patch. SRPT is normally reachable over an RDMA fabric rather than directly from the public Internet. The supplied material does not establish whether a non-administrative tenant, container, or ordinary local user can create the required RDMA connection and SRP session. Therefore `HostAdminRequired=UNKNOWN` and `NamespaceScopedPrivilege=UNKNOWN`. No special physical hardware condition is proven beyond an SRPT-capable RDMA deployment. No concrete race is involved. 4. Primitive and severity interpretation The established primitive is stale bookkeeping after an allocation-unwind failure. The heap-backed `rw_ctxs` allocation is freed, while the associated counters retain values for contexts that no longer exist. This can make later send-queue availability accounting subtract an incorrect amount. Although `rw_ctxs` is dangling before the fix, the available evidence does not show a later stale-pointer dereference or use of freed memory. This is therefore not a confirmed UAF. It is an invalid-state and accounting defect, classified as `CLASS_C`. The demonstrated or directly supported consequence is I O disruption or denial of service through incorrect SQ-credit accounting. A stronger consequence such as post-free memory corruption, information disclosure, privilege escalation, or arbitrary kernel write is speculative and not supported by the supplied call paths. `ImportantCandidate=NO` because no meaningful unresolved active-object lifetime primitive is established. `AutoDowngradeAllowed=YES` because the patch evidence supports a constrained accounting/availability issue rather than active kernel memory corruption. 5. One-sentence report phrase An SRPT allocation-unwind failure can leave stale RDMA context counters and a dangling pointer, causing incorrect send-queue credit accounting and potential SRPT I O denial of service. 6. Manual review recommendation MANUAL CHECK RECOMMENDED Confirm the callers of `srpt_alloc_rw_ctxs()` and the later uses of `ioctx->rw_ctxs`, `n_rw_ctx`, and `n_rdma` to determine whether any path dereferences the freed pointer or whether the effect is limited to SQ-credit accounting. 7. Call-site confidence Call-site confidence: medium ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: RDMA/srpt: Fix srpt_alloc_rw_ctxs() unwind counters [ Upstream Commit: af00051dbc9f467d4840ec709680660a3f8990fa Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=af00051dbc9f467d4840ec709680660a3f8990fa Changed files: drivers/infiniband/ulp/srpt/ib_srpt.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=af00051dbc9f467d4840ec709680660a3f8990fa ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-100075 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-100075 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:H/PR:L/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS score: 4.8 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: 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).