From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-68232][LOW] drm/gpusvm: Fix MM reference leak in drm_gpusvm_range_evict Date: Mon, 10 Aug 2026 16:39:48 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-68232 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: a2212fef8e18724e06432fce01fa257296d9f053 List-Id: CVE: CVE-2026-68232 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: drm/gpusvm: Fix MM reference leak in drm_gpusvm_range_evict Commit: a2212fef8e18724e06432fce01fa257296d9f053 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a2212fef8e18724e06432fce01fa257296d9f053 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68232 Analysis date: Mon, 10 Aug 2026 16:39:48 -0400 ActionableScore: 2 ActionableScore lower bound: 1 Actionable bucket: Ordinary Moderate / Low-like Manual review required: NO Summary: A missing `mmput(mm)` in `drm_gpusvm_range_evict()` on the `kvmalloc_array()` failure path can leak `mm` references and may allow a local process with GPU SVM or DRM access to cause resource-exhaustion DoS under memory pressure. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68232 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68232 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-2026-68232 LOW 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-772;*CWE-401;CWE-404;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.5';DESCR 'A reference leak in drm/gpusvm can occur when drm_gpusvm_range_evict() gets an mm reference and then kvmalloc_array() fails before the reference is released. A local process with access to the GPU SVM or DRM device interface may be able to trigger the error path and accumulate leaked mm references, especially with large ranges or memory pressure. For the CVSS the PR:L is used because reliable triggering requires local code execution and access to the relevant GPU or DRM interface, but not full administrator privileges in typical render node deployments. The issue is not network reachable. Impact is primarily denial of service through resource exhaustion. No confidentiality or integrity impact is assigned because the patch indicates a reference leak and does not show a UAF, OOB access, information leak, or write primitive.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2) SKIP CVE-2026-68232 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: 99624bdff8670795b678eafa6509aaad3a5c0175 YES NO NO unknown MAYBE SIMPLEFIX LEAK HARDWARE INCREASED_FROM_LOW_BASED_ON_HIGHCVSSSCORE DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 - - 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 * Local unprivileged trigger: +1 A local process with access to the relevant DRM/GPU SVM interface may be able to call the affected path. This does not appear to require full host root in typical render-node style deployments. * Availability impact realistic: +1 The leaked `mm` reference can retain process address-space resources and may contribute to resource exhaustion if the failure path is triggered repeatedly. * Hard or unreliable trigger condition: -1 The leak occurs only after `kvmalloc_array()` fails, so reliable triggering likely requires large ranges, memory pressure, or repeated attempts. * Resource leak only: +0 The patch fixes a missing `mmput(mm)` on an allocation failure path. It does not show UAF, OOB access, write primitive, type confusion, refcount takeover, or attacker-controlled reuse. * Paranoid resource-exhaustion interpretation: +1 In the worst defensible case, repeated local triggering could accumulate leaked `mm` references and cause stronger DoS behavior, but this remains a resource leak class issue. ## 3. Reachability analysis The bug is locally reachable through the GPU SVM or DRM path if the hardware, driver, and userspace interface are available. It is not network reachable. Namespaces or containers may matter if DRM render nodes are delegated into containers, but the attacker still needs local code execution and access to the device node. The failure path depends on `kvmalloc_array()` returning `NULL`, so practical exploitation is less direct than a normal ioctl crash path. Call-site confidence: medium. The immediate leak is explicit in the patch, but broader caller reachability and exact user control over `npages` are not fully shown in the provided diff. ## 4. Severity interpretation This behaves like an ordinary Moderate or Low-like kernel resource leak, not an Important-class memory corruption issue. The theoretical impact is denial of service via reference/resource exhaustion. Realistic exploitation evidence for privilege escalation, confidentiality impact, integrity impact, UAF reclaim, or arbitrary write is not present in the patch context. ## 5. One-sentence report phrase A missing `mmput(mm)` in `drm_gpusvm_range_evict()` on the `kvmalloc_array()` failure path can leak `mm` references and may allow a local process with GPU SVM or DRM access to cause resource-exhaustion DoS under memory pressure. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED This is a local allocation-failure reference leak without evidence of memory corruption, security-boundary bypass, privilege escalation, or network reachability. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/gpusvm: Fix MM reference leak in drm_gpusvm_range_evict Commit: a2212fef8e18724e06432fce01fa257296d9f053 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a2212fef8e18724e06432fce01fa257296d9f053 Commit description: If kvmalloc_array() fails in drm_gpusvm_range_evict(), the MM reference acquired earlier is not released, resulting in a reference leak. Fix this by dropping the MM reference on the kvmalloc_array() failure path. Fixes: 99624bd ("drm/gpusvm: Add support for GPU Shared Virtual Memory") Cc: stable@vger.kernel.org Signed-off-by: Matthew Brost Reviewed-by: Himal Prasad Ghimiray Link: https://patch.msgid.link/20260714170025.3487974-1-matthew.brost@intel.com Signed-off-by: Greg Kroah-Hartman Changed files: drivers/gpu/drm/drm_gpusvm.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=a2212fef8e18724e06432fce01fa257296d9f053 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68232 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68232 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: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: 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).