From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-98910][LOW] drm/amdkfd: Unwind debug trap enable on copy_to_user failure [ Upstream Date: Tue, 27 Oct 2026 00:34:12 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-98910 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: 641be20110cdfb6d921605adb42a764a0fccac54 List-Id: CVE: CVE-2026-98910 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: drm/amdkfd: Unwind debug trap enable on copy_to_user failure [ Upstream Commit: 641be20110cdfb6d921605adb42a764a0fccac54 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=641be20110cdfb6d921605adb42a764a0fccac54 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98910 Analysis date: Tue, 27 Oct 2026 00:34:12 -0400 ActionableScore: 1 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate Manual review required: NO Summary: A KFD debug-trap enable error failed to unwind file/process references and active trap bookkeeping, causing persistent resource retention and inconsistent later debug operations. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-98910 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98910 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-2026-98910 LOW https://www.kernelcve.org/list/?q=CVE-2026-98910 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=1 LEGACY=LOW RESULT=DIFF TEMP_DISTANCE_MERGE_SKIP=AEGIS_NO_POSITIVE_SEVERITY_EVIDENCE (final Legacy and Aegis differ; FINAL: LOW, Aegis: MODERATE_KPANIC) 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:L';*CWE-772;CWE-911;CWE-459;BEST CVSS score: '3.3';DESCR 'A cleanup failure in kfd_dbg_trap_enable leaves the debug trap active after copy_to_user returns an error. The stale state includes debug_trap_enabled, an event file reference, a process reference, and an incorrect debugged process count, which can disrupt later DISABLE or ENABLE operations and retain resources. For the CVSS the PR:L value is selected because exploitation requires a local user context with access to the KFD debug trap interface and a suitable target process. The demonstrated primitive is persistent state and reference retention rather than UAF, OOB access, or memory corruption. The issue is not directly network reachable and no reliable host wide resource exhaustion path is established. Automated impact decision path. The original SimpleNet classifier selected MODERATE_KPANIC. The primary LLM estimated paranoid CVSS 3.3 and the production ActionableScore returned 1 with recommendation Ordinary Moderate. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were CVSS and initial triage stage MODERATE_KPANIC to MODERATE because the CVSS score, vector or bug class threshold rule was applied. ActionableScore thresholds stage MODERATE to LOW because the ActionableScore threshold rule was applied. final reconciliation stage LOW to LOW because KP specialist did not establish a qualifying panic and the cross model evidence reconciliation rule was applied. 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 DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS and DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 and KPANIC_UNSUPPORTED_REMOVED and V64_AEGIS_UNSUPPORTED_PROMOTION_BLOCKED. The independent weaker Aegis shadow evaluated CVSS 3.3 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 LOW.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1) MAYBE DANGER HARDWARE DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 KPANIC_UNSUPPORTED_REMOVED V64_AEGIS_UNSUPPORTED_PROMOTION_BLOCKED - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=1 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=UNKNOWN NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=NO ManualReview=NO 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 stronger patch-supported primitive. * Final recommended bucket: **Ordinary Moderate**:: 2. Signal breakdown * **+1 Concrete persistent kernel resource/reference leak:** after successful trap activation, `copy_to_user()` failure previously retained the target process reference and debug event file reference. It also left `debugged_process_count` and `debug_trap_enabled` inconsistent. * **+0 crash/strong DoS:** later ENABLE/DISABLE disruption is described, but no host-wide crash or material exhaustion is established. * No UAF, OOB write, double release, controlled corruption, disclosure, authorization bypass, or protected-resource modification is shown. * The retained file and process references are scored once; the associated counter and flag imbalance are not separate resource-leak points. * B4-PENDING does not apply: the patch restores error unwinding, not a mandatory authorization guard or DENY-to-ALLOW decision. 3. Reachability analysis The supplied summary grounds a local user context with KFD debug-trap access and a suitable target, but the ioctl caller, device-node permissions, target authorization checks, and complete credential requirements are absent. Therefore host-admin and UID-0 requirements remain unknown rather than assumed absent. No namespace-scoped capability, prior host setup, special timing, network reachability, or unusual hardware requirement is demonstrated. A failing userspace destination can plausibly force `copy_to_user()` failure once the interface is accessible. 4. Primitive and severity reading The exact defect is incomplete rollback of already-active debug state: references remain held and structured trap bookkeeping remains enabled after the operation reports failure. This is persistent invalid state/resource retention, not post-lifetime use; the retained references prevent premature lifetime end. It is CLASS_C because the shown consequence is operational disruption and leakage without a separately useful corruption primitive. Important-grade leverage is neither shown nor materially unresolved, so automatic Moderate handling remains appropriate. 5. One-sentence report phrase A KFD debug-trap enable error failed to unwind file/process references and active trap bookkeeping, causing persistent resource retention and inconsistent later debug operations. 6. Manual review advice NO MANUAL CHECK NEEDED The patch shows a bounded cleanup defect without UAF, memory corruption, authorization bypass, or established host-wide exhaustion. 7. Call-site confidence Call-site confidence: medium ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/amdkfd: Unwind debug trap enable on copy_to_user failure [ Upstream Commit: 641be20110cdfb6d921605adb42a764a0fccac54 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=641be20110cdfb6d921605adb42a764a0fccac54 Changed files: drivers/gpu/drm/amd/amdkfd/kfd_debug.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=641be20110cdfb6d921605adb42a764a0fccac54 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-98910 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98910 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:L The Best / paranoid CVSS score: 3.3 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).