From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-68268][LOW] drm/xe: Return error on non-migratable faults requiring devmem Date: Mon, 10 Aug 2026 20:22:21 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-68268 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: 1 X-AL-KERNEL-Commit: 90a8a938e0caecc9ee9dec3eb9eda92d66ba02a3 List-Id: CVE: CVE-2026-68268 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: drm/xe: Return error on non-migratable faults requiring devmem Commit: 90a8a938e0caecc9ee9dec3eb9eda92d66ba02a3 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=90a8a938e0caecc9ee9dec3eb9eda92d66ba02a3 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68268 Analysis date: Mon, 10 Aug 2026 20:22:21 -0400 ActionableScore: 2 ActionableScore lower bound: 1 Actionable bucket: Ordinary Moderate / Low-like Manual review required: NO Summary: A drm xe SVM page fault error-handling bug could incorrectly report success for a non-migratable devmem fault, allowing a local GPU workload to trigger fault-handling failure or denial of service without evidence of memory corruption or privilege escalation. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68268 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68268 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-2026-68268 LOW CHECK WITH IMPACT FROM ORIG NN LOW Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';CWE-703;CWE-755;CWE-252;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.7';DESCR 'A logic error in the drm xe SVM page fault path could report success for a non migratable fault that requires devmem. The handler set EACCES but jumped to a cleanup label that could squash the error, so upper layers could continue as if the fault had been handled even though the required devmem migration was not allowed. For the CVSS the PR:L is used because a local user or process with access to the Xe DRM render interface and an SVM capable workload is needed to trigger the fault path. The issue is not network reachable and requires local GPU access. Impact is primarily denial of service or GPU workload failure due to repeated unresolved faults or incorrect fault completion, with no clear evidence of memory corruption or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2) SKIP CVE-2026-68268 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: 4208fac3dce52d4328007028ec88dd5d0e78dcf2 YES NO NO unknown MAYBE SIMPLEFIX HARDWARE - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=2 ActionableScoreLower=1 ## 1. ActionableScore * Conservative score: 1 * Paranoid score: 2 * Final recommended bucket: **Ordinary Moderate / Low-like**:: ## 2. Signal breakdown Conservative signals: * Local unprivileged trigger: +1. A local process with access to the Xe DRM render interface and an SVM-capable workload may be able to reach the SVM fault path. * Rare / configuration-dependent path: -1. The issue depends on Intel Xe SVM, devmem-only fault handling, and a non-migratable range condition. * Availability impact realistic: +1. Incorrectly squashing -EACCES may cause unresolved GPU faults, workload failure, or driver recovery issues. Conservative total: 1 Paranoid additional interpretation: * Reliable kernel crash / strong DoS: +1. If upper layers treat the fault as handled and repeatedly continue into an invalid fault state, a stronger GPU/driver DoS is technically possible, but not demonstrated by the patch. Paranoid total: 2 Not awarded: * No generic memory corruption. The patch shows incorrect error propagation, not UAF, OOB access, double free, type confusion, or arbitrary write. * No privilege escalation plausible. There is no demonstrated corruption primitive or security boundary bypass. * No confidentiality or integrity impact. The visible consequence is failure to propagate an access error, not data disclosure or unauthorized modification. * No network reachability. This is a local DRM/GPU fault handling path. ## 3. Reachability analysis A local user or local process with access to the Xe DRM render node and an SVM-capable GPU workload is the most plausible trigger. In many desktop or compute environments, render node access can be available to non-root users, so PR:L is more appropriate than PR:H for practical triage. Containers may matter only if the DRM device node is passed through to the container. The path is not remotely reachable and depends on specific Xe GPU SVM/devmem behavior, so exposure is narrower than common kernel syscall or networking paths. Call-site confidence: medium. The patch includes the affected fault-handler branch, but not all upper-layer callers and recovery behavior. ## 4. Severity interpretation This behaves like an ordinary Moderate or Low-like local availability issue. Theoretical impact is a GPU workload or driver DoS caused by incorrect fault completion. Realistic exploitation evidence for memory corruption, privilege escalation, or cross-boundary data access is not present in the supplied patch or commit message. The paranoid score stays low because the bug class is error-handling logic, not a lifetime or memory-safety primitive. ## 5. One-sentence report phrase A drm xe SVM page fault error-handling bug could incorrectly report success for a non-migratable devmem fault, allowing a local GPU workload to trigger fault-handling failure or denial of service without evidence of memory corruption or privilege escalation. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED This can be handled as a low-priority local DoS/error-propagation issue unless additional evidence appears showing a concrete memory corruption primitive, host-wide kernel crash, or privilege boundary bypass. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/xe: Return error on non-migratable faults requiring devmem Commit: 90a8a938e0caecc9ee9dec3eb9eda92d66ba02a3 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=90a8a938e0caecc9ee9dec3eb9eda92d66ba02a3 Commit description: Non-migratable faults that require devmem incorrectly jump to the 'out' label, which squashes the error code intended to be returned to the upper layers. Fix this by returning -EACCES instead. Reported-by: Sashiko Fixes: 4208fac ("drm/xe: Add more SVM GT stats") Cc: stable@vger.kernel.org Signed-off-by: Matthew Brost Reviewed-by: Francois Dugast Link: https://patch.msgid.link/20260617135101.1245574-1-matthew.brost@intel.com (cherry picked from commit c4508ed ) Signed-off-by: Thomas Hellström Signed-off-by: Greg Kroah-Hartman Changed files: drivers/gpu/drm/xe/xe_svm.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=90a8a938e0caecc9ee9dec3eb9eda92d66ba02a3 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68268 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68268 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:L The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS score: 4.7 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: 1 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).