From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-68262][MODERATE 7.0] drm/imagination: Fix user array stride in pvr_set_uobj_array() Date: Mon, 10 Aug 2026 11:44:24 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-68262 X-AL-KERNEL-Priority: MODERATE 7.0 X-AL-KERNEL-Severity: MODERATE 7.0 X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 5 X-AL-KERNEL-ActionableScore-Lower: 4 X-AL-KERNEL-Commit: bbebc39a70f6fc9b02637c8624349e30325873cb List-Id: CVE: CVE-2026-68262 Priority: MODERATE 7.0 AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: drm/imagination: Fix user array stride in pvr_set_uobj_array() Commit: bbebc39a70f6fc9b02637c8624349e30325873cb Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bbebc39a70f6fc9b02637c8624349e30325873cb Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68262 Analysis date: Mon, 10 Aug 2026 11:44:24 -0400 ActionableScore: 5 ActionableScore lower bound: 4 Actionable bucket: Actionable Moderate at minimum Manual review required: YES Summary: A local DRM Imagination ioctl path can mis-handle user supplied array stride in `pvr_set_uobj_array()`, causing later `copy_to_user()` calls to read from wrong kernel addresses and potentially disclose kernel memory, with possible DoS if the invalid read faults. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68262 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68262 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 7.0 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-2026-68262 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:H/I:N/A:H';CWE-125;*CWE-200;CWE-682;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L';BEST CVSS score: '7.1';DESCR 'A kernel out of bounds read can occur in the drm imagination pvr_set_uobj_array path because the slow path advanced the userspace pointer by the kernel object size and advanced the kernel pointer by the userspace stride. When the userspace stride is larger than the kernel object size, later copy_to_user operations may read from wrong kernel addresses and expose kernel memory to userspace. When the userspace stride is smaller, data is copied to wrong userspace offsets, but this does not show a kernel write primitive. For the CVSS the PR:L is used because a local process with access to the DRM render or card device can call the affected ioctl path. The issue is not network reachable. Impact is primarily confidentiality disclosure, with possible denial of service if the invalid kernel read faults.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 5) SKIP CVE-2026-68262 UNKNOWN SKIP No affected files built, so skip this CVE NO - - unknown MAYBE READ SIMPLEFIX HARDWARE LINUS INCREASED_TO_MODERATE7_FROM_MODERATE_BASED_ON_GUESSCVSS DECREASED_TO_MODERATEREG_BASED_ON_FALSEPOSCHECKOFKP - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=5 ActionableScoreLower=4 ## 1. ActionableScore * Conservative score: 4 * Paranoid score: 5 * Final recommended bucket: **Actionable Moderate at minimum**:: ## 2. Signal breakdown Conservative signals: * Local unprivileged trigger: +1. A local process with access to the affected DRM Imagination device ioctl path can influence `out->stride`. * Memory corruption, weak/indirect corruption candidate: +1. The bug creates wrong kernel pointer advancement and a kernel out-of-bounds read source for `copy_to_user`, but does not show an OOB write, UAF, reclaim, type confusion, or arbitrary write. * Confidentiality impact plausible: +1. For larger userspace strides, later copies may read from wrong kernel addresses and disclose unintended kernel memory to userspace. * Local high-control device API refinement: +1. The userspace controlled stride directly affects kernel/userspace array layout and pointer arithmetic in a GPU ioctl helper. Paranoid additional signal: * Availability impact realistic: +1. If the incorrect kernel source pointer crosses into an invalid or faulting kernel address range, the copy path may cause a kernel fault or crash. This is plausible but not demonstrated as the primary impact. Not awarded: * No strong generic memory corruption +2. The demonstrated primitive is read-side pointer miscalculation, not OOB write or controlled overwrite. * No privilege escalation plausible +2. There is no supported reclaim, overwrite, callback, refcount, or object-confusion primitive. * No integrity impact. The smaller-stride case writes to wrong userspace offsets, not kernel memory. * No remote/network signal. This is a local DRM ioctl path. ## 3. Reachability analysis The bug is locally reachable by a process that can open the relevant DRM Imagination device node and issue the affected ioctl path. In many deployments, DRM render nodes are accessible to local desktop or graphics users, so PR:L is the practical assumption rather than PR:H. Containers and sandboxes may reduce or remove access depending on whether the DRM device is passed through. The path is hardware and driver dependent, so exposure is narrower than generic DRM core, but it remains an ordinary local device interface when the driver is present. Call-site confidence: medium. The patch shows the affected helper and the user/kernel copy behavior, but not all ioctl callers. ## 4. Severity interpretation This behaves as an actionable Moderate issue, mainly because it provides a plausible kernel information disclosure primitive through `copy_to_user`. The realistic evidence supports local kernel memory disclosure and possible crash, not direct privilege escalation. The paranoid score is higher because kernel information disclosure from a local device ioctl can be useful in exploit chains and should not be auto-closed without manual review. ## 5. One-sentence report phrase A local DRM Imagination ioctl path can mis-handle user supplied array stride in `pvr_set_uobj_array()`, causing later `copy_to_user()` calls to read from wrong kernel addresses and potentially disclose kernel memory, with possible DoS if the invalid read faults. ## 6. Manual review recommendation MANUAL CHECK REQUIRED Reason: the patch supports a concrete kernel out-of-bounds read to userspace via `copy_to_user`, which is a plausible information disclosure primitive even though no direct LPE or kernel write primitive is shown. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/imagination: Fix user array stride in pvr_set_uobj_array() Commit: bbebc39a70f6fc9b02637c8624349e30325873cb Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bbebc39a70f6fc9b02637c8624349e30325873cb Commit description: pvr_set_uobj_array() copies an array of kernel objects to a userspace array whose element size is described by out->stride. When out->stride is different from the kernel object size, the slow path advances the userspace pointer by the kernel object size and the kernel pointer by the userspace stride. This reverses the intended layout. For larger userspace strides, later copies read from the wrong kernel addresses. For smaller userspace strides, later copies are written at the wrong userspace offsets. The padding clear is also done only for the first element instead of the padding area for each element. Advance the userspace pointer by out->stride and the kernel pointer by obj_size, and clear per-element padding while the current userspace pointer is still available. Fixes: f99f5f3 ("drm/imagination: Add GPU ID parsing and firmware loading") Cc: stable@vger.kernel.org # v6.8+ Reviewed-by: Alessio Belle Signed-off-by: Shuvam Pandey Link: https://patch.msgid.link/6a456012.eb165e5c.113c2a.b71d@mx.google.com Signed-off-by: Alessio Belle Signed-off-by: Greg Kroah-Hartman Changed files: drivers/gpu/drm/imagination/pvr_drv.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=bbebc39a70f6fc9b02637c8624349e30325873cb ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68262 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68262 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:H/I:N/A:L The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H The Best / paranoid CVSS score: 7.1 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: 4 Paranoid ActionableScore: 5 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 7.0 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).