From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-98905][LOW] drm/amdkfd: Properly acquire queue buffers in CRIU restore [ Upstream Date: Mon, 26 Oct 2026 16:33:03 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-98905 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: e2dbdd14c3352483a89e4a9afda05d0f3fcc2c83 List-Id: CVE: CVE-2026-98905 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: drm/amdkfd: Properly acquire queue buffers in CRIU restore [ Upstream Commit: e2dbdd14c3352483a89e4a9afda05d0f3fcc2c83 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e2dbdd14c3352483a89e4a9afda05d0f3fcc2c83 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98905 Analysis date: Mon, 26 Oct 2026 16:33:03 -0400 ActionableScore: 2 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate Manual review required: NO Summary: A locally accessible AMD KFD CRIU restore operation can pass unacquired NULL queue-buffer state into queue creation, plausibly causing a kernel denial of service. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-98905 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98905 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-2026-98905 LOW https://www.kernelcve.org/list/?q=CVE-2026-98905 CHECK WITH IMPACT FROM ORIG NN LOW | 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:H';CWE-665;**CWE-476;CWE-404;BEST CVSS score: '5.5';DESCR 'The AMD KFD CRIU restore path copied queue addresses into queue_properties but did not acquire and validate the associated user queue buffers before calling pqm_create_queue. This left buffer related fields or references uninitialized and potentially NULL when later queue creation code expected valid acquired objects. A crafted or inconsistent restore operation may therefore cause queue restoration failure or a kernel NULL pointer fault with denial of service impact. For the CVSS the PR:L value is selected because triggering requires a local process with access to the KFD device and the CRIU queue restore interface. The issue is not directly network reachable. There is no concrete evidence of UAF, OOB access, arbitrary write, information disclosure, or privilege escalation, so the grounded impact is availability only. Automated impact decision path. The original SimpleNet classifier selected LOW. The primary LLM estimated paranoid CVSS 5.5 and the production ActionableScore returned 2 with recommendation Ordinary Moderate. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were 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 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.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2) MAYBE INIT HARDWARE KPANIC_UNSUPPORTED_REMOVED V64_AEGIS_UNSUPPORTED_PROMOTION_BLOCKED - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=2 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=NO NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=NO ManualReview=RECOMMENDED AutoDowngradeAllowed=YES RequiresHostUID0=NO AuthorizationDecisionBypass=NO ProtectedResourceImpact=NONE B4PendingReview=NO B4PendingConfirmed=NO 1. ActionableScore * Raw base score: 2. * Conservative score: 2; no floor or cap applied. * Raw paranoid score: 2. * Paranoid score: 2; stronger consequences are not supported. * Final recommended bucket: **Ordinary Moderate**:: 2. Signal breakdown * +1 weak/invalid structured-state consumption: `queue_properties` is zeroed, but the CRIU path omitted `kfd_queue_acquire_buffers()`, leaving buffer-related fields or references NULL when passed to `pqm_create_queue()`. * +1 reliable kernel crash/DoS concern: subsequent queue creation expects acquired, non-NULL buffer state, making a NULL-pointer fault plausible. * No separate availability point: it would duplicate the same prospective fault. * No UAF, OOB read/write, repeated release, controlled overwrite, disclosure, or authorization bypass is shown. * NEW52/B5-R does not apply: there is no confirmed retry-accumulated heap OOB write or later consumption of OOB-corrupted state. * Controlled reclaim, arbitrary write, protected-state modification, and privilege escalation are not shown. 3. Reachability analysis The supplied triage evidence grounds a local process with KFD-device and CRIU queue-restore access and characterizes it as PR:L, supporting below-host-administrator reachability rather than ordinary unrestricted local access. Numeric host UID 0 is not shown as required. The patch does not establish namespace-scoped permissions, so `NamespaceScopedPrivilege` remains unknown. There is no network path, special race, retry sequence, or unusual physical-device requirement shown. 4. Primitive and severity reading The exact defect is failure to acquire and validate user queue buffers before creating a restored queue. The consumed state is active queue-creation metadata, but the only grounded consequence is missing/NULL references and a possible kernel fault. This is not a lifetime violation or demonstrated memory corruption, so it is CLASS_C. The added cleanup calls handle buffers only after the newly added acquisition succeeds; they do not demonstrate a pre-existing double release. Important-grade leverage past the crash is absent. Therefore `ImportantCandidate=NO` and automatic Moderate downgrade remains allowed. 5. One-sentence report phrase A locally accessible AMD KFD CRIU restore operation can pass unacquired NULL queue-buffer state into queue creation, plausibly causing a kernel denial of service. 6. Manual review advice MANUAL CHECK RECOMMENDED Confirm the exact KFD/CRIU ioctl permissions and the downstream NULL dereference, since `pqm_create_queue()` is not included. 7. Call-site confidence Call-site confidence: medium ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/amdkfd: Properly acquire queue buffers in CRIU restore [ Upstream Commit: e2dbdd14c3352483a89e4a9afda05d0f3fcc2c83 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e2dbdd14c3352483a89e4a9afda05d0f3fcc2c83 Changed files: drivers/gpu/drm/amd/amdkfd/kfd_process_queue_manager.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=e2dbdd14c3352483a89e4a9afda05d0f3fcc2c83 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-98905 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98905 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).