From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-43195][MODERATE REGULAR] drm/amdgpu: validate user queue size constraints [ Upstream Date: Sat, 01 Aug 2026 13:02:49 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-43195 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: 3 X-AL-KERNEL-ActionableScore-Lower: 2 X-AL-KERNEL-Commit: cf2a37be899dc1b01f53bf1d0157330eaf3e3f55 List-Id: CVE: CVE-2026-43195 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: drm/amdgpu: validate user queue size constraints [ Upstream Commit: cf2a37be899dc1b01f53bf1d0157330eaf3e3f55 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=cf2a37be899dc1b01f53bf1d0157330eaf3e3f55 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-43195 Analysis date: Sat, 01 Aug 2026 13:02:49 -0400 ActionableScore: 3 ActionableScore lower bound: 2 Actionable bucket: Borderline, manual review recommended Manual review required: YES Summary: AMDGPU user queue creation failed to validate that queue_size is a power of two and at least AMDGPU_GPU_PAGE_SIZE, allowing a local GPU user to submit invalid queue parameters that may cause GPU faults or degraded GPU availability. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-43195 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-43195 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: YES A detailed explanation of the methodology and priority rules is included at the end of this message. ====================================================================== AL-KERNEL CLASSIFICATION RESULT ====================================================================== CVE-2026-43195 MODERATE 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-20;CWE-1284;**CWE-400;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.5';DESCR 'AMDGPU user queue creation did not validate that the queue size is a power of 2 and at least AMDGPU_GPU_PAGE_SIZE. Invalid sizes can break ring buffer wrapping assumptions or create undersized queue configurations, which may lead to GPU faults or unexpected device behavior. For the CVSS the PR:L is used for the paranoid score because local DRM render node or GPU device access may be available to non root users in common desktop and compute deployments. The issue is not network reachable and requires local access to the AMDGPU user queue interface. Impact is primarily denial of service through GPU fault, reset, or degraded GPU availability. No concrete kernel memory corruption or privilege escalation primitive is visible from the patch context.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline, manual review recommended (with actual score 3) SKIP CVE-2026-43195 SKIP No affected files built, so skip this CVE NO - - unknown MAYBE HARDWARE MEMORY DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=3 ActionableScoreLower=2 ## 1. ActionableScore * Conservative score: 2 * Paranoid score: 3 * Final recommended bucket: **Borderline, manual review recommended**:: ## 2. Signal breakdown Triggered signals: * Local unprivileged trigger: +1 AMDGPU DRM render nodes or GPU device interfaces are commonly reachable by local non-root users in desktop and compute deployments. * Availability impact realistic: +1 The commit explicitly mentions GPU faults or unexpected behavior. This supports local GPU DoS, reset, or degraded GPU availability, but not a proven host-wide kernel crash. * Broad/default/common subsystem or broadly deployed exposure: +1 for paranoid score only AMDGPU is a common DRM driver on affected hardware, and user queue creation is a realistic local GPU interface. This is hardware-dependent, so I count it only in the paranoid score. Not triggered: * Generic memory corruption: +0 The patch only adds input validation for queue_size. It does not show UAF, OOB write, double free, type confusion, refcount misuse, or arbitrary write. * Privilege escalation plausible: +0 No concrete LPE primitive is visible from the patch. * High-control kernel data-plane API: +0 This is a rich device API, but the patch does not show attacker control over kernel object lifetime, callbacks, refcounts, DMA mappings, or page ownership. * Reliable kernel crash / strong DoS: +0 The described failure is GPU faults or unexpected behavior, not a demonstrated kernel panic or reliable system-wide crash. Caps and constraints: * Validation-only unspecified-corruption cap applies. Conservative score should remain at or below 4 and paranoid score at or below 5. * The patch rejects invalid input with EINVAL and does not describe a downstream corruption primitive. ## 3. Reachability analysis A local user with access to the AMDGPU user queue interface can potentially trigger the invalid queue_size path. In typical systems this may include non-root users with access to DRM render nodes or GPU compute interfaces. This is not network reachable. Containers may matter if GPU devices are passed through or render nodes are exposed into the container. If the device node is not accessible to untrusted users, practical reachability is much lower. The affected path is hardware and driver dependent. It is relevant on AMDGPU systems that expose user queues, but it is not a generic kernel-wide path. Call-site confidence: medium. The validation function and immediate rejected fields are visible, but the deeper hardware fault behavior is described only at a high level. ## 4. Severity interpretation This behaves more like a low-to-moderate local device DoS than an Important-class kernel vulnerability. The theoretical concern is that invalid queue sizes can violate hardware ring buffer assumptions or cause undersized allocations, but the patch does not show a memory corruption primitive in kernel memory. Realistic impact is GPU fault, reset, or degraded GPU availability. There is not enough evidence for confidentiality impact, integrity impact, or privilege escalation. ## 5. One-sentence report phrase AMDGPU user queue creation failed to validate that queue_size is a power of two and at least AMDGPU_GPU_PAGE_SIZE, allowing a local GPU user to submit invalid queue parameters that may cause GPU faults or degraded GPU availability. ## 6. Manual review recommendation MANUAL CHECK RECOMMENDED Reason: this is probably not Important and should not be treated as proven memory corruption, but manual confirmation is useful because local render node users may be unprivileged and the exact GPU fault behavior depends on hardware and queue handling. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/amdgpu: validate user queue size constraints [ Upstream Commit: cf2a37be899dc1b01f53bf1d0157330eaf3e3f55 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=cf2a37be899dc1b01f53bf1d0157330eaf3e3f55 Changed files: drivers/gpu/drm/amd/amdgpu/amdgpu_userq.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=cf2a37be899dc1b01f53bf1d0157330eaf3e3f55 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-43195 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-43195 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:L/PR:L/UI:N/S:U/C:N/I:N/A:L 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: 2 Paranoid ActionableScore: 3 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).