From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-68275][MODERATE REGULAR] drm/amdgpu: check amdgpu_vm_bo_find() result in GET_MAPPING_INFO Date: Mon, 10 Aug 2026 19:08:15 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-68275 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: 4 X-AL-KERNEL-ActionableScore-Lower: 3 X-AL-KERNEL-Commit: ddba17b3dfa0efc80d6c98621c2fb7af66adb622 List-Id: CVE: CVE-2026-68275 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: drm/amdgpu: check amdgpu_vm_bo_find() result in GET_MAPPING_INFO Commit: ddba17b3dfa0efc80d6c98621c2fb7af66adb622 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ddba17b3dfa0efc80d6c98621c2fb7af66adb622 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68275 Analysis date: Mon, 10 Aug 2026 19:08:15 -0400 ActionableScore: 4 ActionableScore lower bound: 3 Actionable bucket: Borderline, manual review recommended Manual review required: YES Summary: A local user with AMDGPU render-device access can request mapping information for an unmapped buffer object and trigger a NULL pointer dereference in the GEM ioctl path, causing a kernel DoS without evidence of confidentiality, integrity, or privilege-escalation impact. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68275 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68275 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-2026-68275 MODERATE CHECK WITH IMPACT FROM ORIG NN MODERATE 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-476;*CWE-20;CWE-754;BEST CVSS score: '5.5';DESCR 'A NULL pointer dereference in the AMDGPU GEM_OP_GET_MAPPING_INFO ioctl occurs because amdgpu_vm_bo_find can return NULL when a buffer object has no mapping in the callers VM. The returned pointer was used by amdgpu_vm_bo_va_for_each_valid_mapping, which dereferences bo_va and can crash the kernel when mapping info is requested for an unmapped BO. For the CVSS the PR:L is used because triggering requires local access to the DRM render device, typically through the render group or equivalent device permissions. The issue is not network reachable and is triggered through a local GPU ioctl rather than remote traffic. Impact is denial of service via kernel oops or kernel crash. No direct confidentiality or integrity impact is assigned because the primitive shown by the patch is a NULL dereference, not UAF, OOB access, or controlled memory corruption.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline, manual review recommended (with actual score 4) SKIP CVE-2026-68275 UNKNOWN SKIP No affected files built, so skip this CVE NO - - unknown MAYBE NULLPTR SIMPLEFIX HARDWARE DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=4 ActionableScoreLower=3 ## 1. ActionableScore * Conservative score: 3 * Paranoid score: 4 * Final recommended bucket: **Borderline, manual review recommended** ## 2. Signal breakdown Triggered signals: * Local unprivileged trigger: +1 Any local process with access to the AMDGPU DRM render node can issue the ioctl. This is typically a render group user, not full root. * Reliable kernel crash / strong DoS: +1 The unchecked NULL `bo_va` is dereferenced through `amdgpu_vm_bo_va_for_each_valid_mapping()`, causing a NULL pointer dereference. * Broad/default/common subsystem or broadly deployed exposure: +1 AMDGPU DRM render nodes are common on affected GPU systems and are often exposed to non-root desktop or compute users. Paranoid-only additional signal: * Availability impact realistic: +1 The trigger is simple once render-node access exists: request mapping info for an unmapped BO. If the NULL dereference causes host-wide oops or panic, the availability impact is practical. Not triggered: * Generic memory corruption: +0 The primitive is NULL pointer dereference, not UAF, OOB write, double free, refcount misuse, or type confusion. * Privilege escalation plausible: +0 No reclaim, overwrite, callback control, object confusion, or controlled memory corruption is shown. * Confidentiality / Integrity impact: +0 No read disclosure or write primitive is supported by the patch. * Remote reachable: +0 This is a local DRM ioctl path, not network-triggerable. ## 3. Reachability analysis The bug is reachable by a local process that can open the AMDGPU DRM render device and issue `AMDGPU_GEM_OP_GET_MAPPING_INFO` for a BO that has not been mapped into the caller VM. This commonly corresponds to users in the `render` group or equivalent device ACLs. Namespaces or containers may matter if the GPU render node is passed into a container. In that case, a containerized workload with render-device access may be able to trigger the host kernel bug, but this still remains a local device-interface trigger rather than a remote network issue. The affected path is relevant on systems using AMDGPU with render-node access enabled. Realistic exploitation is a local DoS. There is no evidence of LPE beyond the crash primitive. Call-site confidence: high. The commit message and diff directly identify the ioctl path, the NULL return from `amdgpu_vm_bo_find()`, and the dereference site. ## 4. Severity interpretation This behaves like a Borderline / actionable Moderate local DoS, not an Important-class memory corruption issue. Theoretical severity is limited because the demonstrated primitive is a NULL dereference. Realistic impact is kernel oops or crash from a local render-device user. It should not be upgraded to privilege escalation without additional evidence such as UAF, attacker-controlled reuse, object replacement, arbitrary write, or callback control. ## 5. One-sentence report phrase A local user with AMDGPU render-device access can request mapping information for an unmapped buffer object and trigger a NULL pointer dereference in the GEM ioctl path, causing a kernel DoS without evidence of confidentiality, integrity, or privilege-escalation impact. ## 6. Manual review recommendation MANUAL CHECK RECOMMENDED Reason: the issue is a simple local NULL dereference, but the render-node exposure is common enough that it should not be blindly auto-closed on GPU-enabled systems. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/amdgpu: check amdgpu_vm_bo_find() result in GET_MAPPING_INFO Commit: ddba17b3dfa0efc80d6c98621c2fb7af66adb622 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ddba17b3dfa0efc80d6c98621c2fb7af66adb622 Commit description: The AMDGPU_GEM_OP_GET_MAPPING_INFO path of amdgpu_gem_op_ioctl() looks up the bo_va for the buffer object in the caller's VM via amdgpu_vm_bo_find(), but uses the returned pointer without checking it. amdgpu_vm_bo_find() returns NULL when the BO has no bo_va in that VM, which is the normal case for a BO that has never been mapped. The result is fed straight into amdgpu_vm_bo_va_for_each_valid_mapping(), which expands to list_for_each_entry(mapping, &(bo_va)->valids, list) and dereferences bo_va, causing a NULL pointer dereference. This is reachable by any process able to issue the ioctl (render group) simply by requesting mapping info for an unmapped BO. Return -ENOENT when no bo_va is found, jumping to out_exec so the drm_exec context and GEM object reference are released. Fixes: 4d82724 ("drm/amdgpu: Add mapping info option for GEM_OP ioctl") Reviewed-by: Alex Deucher Signed-off-by: Mario Limonciello Signed-off-by: Alex Deucher (cherry picked from commit 528b193 ) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman Changed files: drivers/gpu/drm/amd/amdgpu/amdgpu_gem.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=ddba17b3dfa0efc80d6c98621c2fb7af66adb622 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68275 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68275 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: 3 Paranoid ActionableScore: 4 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).