From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-64039][LOW] drm/msm/snapshot: fix dumping of the unaligned regions [ Upstream Date: Sun, 19 Jul 2026 17:12:35 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-64039 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: 1 X-AL-KERNEL-ActionableScore-Lower: 0 X-AL-KERNEL-Commit: 8fb070cf95847b29ef6cb15ec2c0de2bf4704676 List-Id: CVE: CVE-2026-64039 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: drm/msm/snapshot: fix dumping of the unaligned regions [ Upstream Commit: 8fb070cf95847b29ef6cb15ec2c0de2bf4704676 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8fb070cf95847b29ef6cb15ec2c0de2bf4704676 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64039 Analysis date: Sun, 19 Jul 2026 17:12:35 -0400 ActionableScore: 1 ActionableScore lower bound: 0 Actionable bucket: Ordinary Moderate / Low-like Manual review required: NO Summary: The MSM DRM snapshot code used incorrect length accounting for unaligned register regions, causing inaccurate dumps and about 16x memory over-allocation in a local diagnostic or recovery path, with impact limited to low-confidence local DoS. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-64039 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64039 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-2026-64039 LOW CHECK WITH IMPACT FROM ORIG NN MODERATE 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:L';CWE-682;CWE-131;**CWE-400;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '2.5';DESCR 'The drm msm snapshot code used incorrect length accounting for register dump regions and could allocate about 16x more memory than needed while also producing inaccurate dumps for unaligned DSI regions. This is a local diagnostic or recovery path issue rather than a packet or remote attack surface. For the CVSS the PR:L is used for the paranoid score because a local unprivileged graphics client may be able to trigger display snapshot paths indirectly through driver error or recovery handling, although direct debugfs snapshot control is usually privileged. The issue is not network reachable. Impact is limited denial of service from unnecessary memory consumption or failed snapshot handling, with no supported path to privilege escalation or arbitrary memory corruption.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 1) SKIP CVE-2026-64039 UNKNOWN SKIP No affected files built, so skip this CVE NO - - unknown MAYBE DANGER SIMPLEFIX HARDWARE LINUS DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=1 ActionableScoreLower=0 ## 1. ActionableScore * Conservative score: 0 * Paranoid score: 1 * Final recommended bucket: **Ordinary Moderate / Low-like** ## 2. Signal breakdown Conservative signals: * Requires admin/root or debug/recovery control in typical deployments: -2. Direct triggering of MSM display snapshot/debug paths is usually privileged or device/recovery specific. * Rare AND difficult-to-reach subsystem/configuration: -1. This is Qualcomm MSM DRM snapshot code, not a broad default kernel path. * Availability impact realistic: +1. The 16x over-allocation can cause failed allocations or local resource pressure in the snapshot path, but the patch does not show a reliable system-wide crash. * No generic memory corruption: +0. The patch fixes incorrect size accounting and over-allocation, not UAF, double-free, OOB write, type confusion, or arbitrary write. * No confidentiality or integrity impact: +0. The diff does not show data disclosure or modification of protected data. Paranoid additional signal: * Local unprivileged indirect trigger: +1. A local graphics client might indirectly contribute to display error or recovery paths that take snapshots, although this is not demonstrated and direct snapshot controls are normally privileged. ## 3. Reachability analysis The affected path is local and device-specific. It is not network reachable. Realistic triggering requires an MSM DRM device and a display snapshot path, usually through debug, diagnostic, crashdump, or recovery handling. In typical deployments this is not an ordinary unprivileged interface, although a local graphics workload could possibly influence display recovery indirectly. Namespaces or containers do not clearly lower the privilege requirement unless the product exposes DRM device access and recovery behavior to sandboxed workloads. Call-site confidence: medium. The patch includes the changed snapshot helper and its direct caller, but not all external paths that initiate snapshot collection. ## 4. Severity interpretation This behaves like a Low or ordinary Moderate issue, not an Actionable Moderate or Important candidate. The main issue is incorrect length accounting causing inaccurate dumps and excessive allocation. Theoretical impact is limited to local availability degradation from memory over-allocation or failed snapshot handling. There is no realistic evidence of privilege escalation, memory corruption, attacker-controlled overwrite, sensitive disclosure, or cross-boundary policy bypass. ## 5. One-sentence report phrase The MSM DRM snapshot code used incorrect length accounting for unaligned register regions, causing inaccurate dumps and about 16x memory over-allocation in a local diagnostic or recovery path, with impact limited to low-confidence local DoS. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED This can be auto-closed or deferred in most triage workflows because it is a device-specific diagnostic path with no demonstrated memory corruption, no network reachability, no privilege escalation primitive, and only limited availability impact. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/msm/snapshot: fix dumping of the unaligned regions [ Upstream Commit: 8fb070cf95847b29ef6cb15ec2c0de2bf4704676 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8fb070cf95847b29ef6cb15ec2c0de2bf4704676 Changed files: drivers/gpu/drm/msm/disp/msm_disp_snapshot_util.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=8fb070cf95847b29ef6cb15ec2c0de2bf4704676 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-64039 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64039 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:H/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:L The Best / paranoid CVSS score: 2.5 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: 0 Paranoid ActionableScore: 1 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).