From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-98938][MODERATE REGULAR] rust: irq: pass RegistrationInner as cookie to request_irq With Date: Tue, 27 Oct 2026 00:47:12 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-98938 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: 1 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: 9a7931e847f338a687e96cde9f37e0cff83ddd84 List-Id: CVE: CVE-2026-98938 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: rust: irq: pass RegistrationInner as cookie to request_irq With Commit: 9a7931e847f338a687e96cde9f37e0cff83ddd84 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9a7931e847f338a687e96cde9f37e0cff83ddd84 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98938 Analysis date: Tue, 27 Oct 2026 00:47:12 -0400 ActionableScore: 1 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate Manual review required: NO Summary: An initialization race lets an immediate IRQ callback dereference an uninitialized device reference, plausibly crashing the kernel without a shown write or privilege-boundary primitive. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-98938 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98938 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-2026-98938 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-98938 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=1 LEGACY=MODERATE RESULT=DIFF (final Legacy and Aegis differ; FINAL: MODERATE, Aegis: MODERATE_KPANIC) Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H';*CWE-457;CWE-362;CWE-824;CWE-665;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.8';DESCR 'An initialization race exists because request_irq can enable the interrupt before the enclosing Registration.inner field has been initialized. An immediate IRQ callback can access registration.inner.device through uninitialized kernel memory, resulting in an invalid object or pointer read and potentially a kernel crash or other undefined behavior. For the CVSS the PR:L value reflects that reliable attacker controlled triggering generally requires local access to a vulnerable Rust driver or its device interface. AC:H reflects the narrow initialization timing window. No direct network trigger is established, and the patch does not demonstrate an OOB write or arbitrary write primitive. Automated impact decision path. The original SimpleNet classifier selected MODERATE. The primary LLM estimated paranoid CVSS 5.8 and the production ActionableScore returned 1 with recommendation Ordinary Moderate. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. No severity changing production threshold or specialist override was recorded. The legacy KP specialist has no review artifact for this run. The legacy FD or DH downgrade specialist has no review artifact for this run. Exact triggered rule markers were V41_INHERITED_KPANIC_PROMOTION_BLOCKED and MANUAL_REVIEW_REQUIRED. The independent weaker Aegis shadow evaluated CVSS 2.6 and ActionableScore 1 with primitive class CLASS_C and manual review REQUIRED. Its independently reconciled impact was MODERATE_KPANIC. The models disagreed but the aggregation rules retained the production result. The final reported impact is MODERATE.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1) MAYBE INIT RACE HARDWARE LINUS V41_INHERITED_KPANIC_PROMOTION_BLOCKED MANUAL_REVIEW_REQUIRED - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=1 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=UNKNOWN NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=NO ManualReview=RECOMMENDED AutoDowngradeAllowed=YES RequiresHostUID0=UNKNOWN AuthorizationDecisionBypass=NO ProtectedResourceImpact=NONE B4PendingReview=NO B4PendingConfirmed=NO 1. ActionableScore * Raw base score: 1. * Conservative score: 1; no floor or cap applied. * Raw paranoid score: 1. * Paranoid score: 1; no technically supported stronger primitive. * Final recommended bucket: **Ordinary Moderate**:: 2. Signal breakdown * +1 weak/indirect corruption candidate: the IRQ callback reads `registration.inner.device()` while `inner` may still be uninitialized, potentially constructing or dereferencing an invalid device reference. * +1 plausible kernel crash: dereferencing the invalid object/pointer can fault in IRQ context. * -1 hard timing requirement: the interrupt must run in the narrow interval after `request_irq()` enables it but before `Devres::new()` finishes installing `registration.inner`. * No UAF, OOB write, disclosure path, attacker-controlled write, controlled reclaim, authorization bypass, or protected-resource impact is shown. * NEW52/B5-R does not apply: there is no retry-accumulated index or confirmed heap OOB write. * No extra availability point: it would duplicate the same possible crash. 3. Reachability analysis The vulnerable callback is clearly reachable from an immediate device interrupt during driver IRQ registration. The supplied source does not identify a userspace ioctl, render-node operation, capability check, or attacker-controlled mechanism that reliably causes the interrupt in this window. Consequently, below-host-admin reachability, host UID requirements, namespace capability scope, and any prior privileged setup remain unresolved. No rare-hardware penalty is applied because rarity is not established. 4. Primitive and severity reading The exact primitive is consumption of incompletely initialized structured state: the old IRQ cookie points to the enclosing registration while its `inner` field is not yet initialized. This is neither a post-lifetime UAF nor a proven memory write. The shown consequence is an invalid pointer/object read with plausible crash or undefined behavior; confidentiality, integrity, and exploitation beyond the fault are speculative. It is therefore CLASS_C, not an Important-preserving Class B/A primitive. Auto-downgrade remains allowed because no material unknown write or trust-boundary primitive is established. 5. One-sentence report phrase An initialization race lets an immediate IRQ callback dereference an uninitialized device reference, plausibly crashing the kernel without a shown write or privilege-boundary primitive. 6. Manual review advice MANUAL CHECK RECOMMENDED Confirm affected Rust-driver exposure and whether an attacker-accessible device operation can reliably generate the initialization-time interrupt. 7. Call-site confidence Call-site confidence: high ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: rust: irq: pass RegistrationInner as cookie to request_irq With Commit: 9a7931e847f338a687e96cde9f37e0cff83ddd84 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9a7931e847f338a687e96cde9f37e0cff83ddd84 Changed files: rust/kernel/irq/request.rs 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=9a7931e847f338a687e96cde9f37e0cff83ddd84 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-98938 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98938 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:L/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:L/I:L/A:H The Best / paranoid CVSS score: 5.8 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: 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: 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).