From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-64153][LOW] drm/msm: Fix iommu_map_sgtable() return value check and avoid WARN [ Upstream Date: Sun, 19 Jul 2026 15:17:35 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-64153 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: 3c2cdb7c07f664b77e2a75b50793b845d5742efa List-Id: CVE: CVE-2026-64153 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: drm/msm: Fix iommu_map_sgtable() return value check and avoid WARN [ Upstream Commit: 3c2cdb7c07f664b77e2a75b50793b845d5742efa Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3c2cdb7c07f664b77e2a75b50793b845d5742efa Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64153 Analysis date: Sun, 19 Jul 2026 15:17:35 -0400 ActionableScore: 1 ActionableScore lower bound: 0 Actionable bucket: Ordinary Moderate / Low-like Manual review required: NO Summary: The drm/msm IOMMU mapping path stored a negative `iommu_map_sgtable()` error in an unsigned variable, causing incorrect error handling, but the visible impact is limited to local GPU mapping failure behavior without demonstrated memory corruption or privilege escalation. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-64153 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64153 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-2026-64153 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:L';CWE-681;CWE-704;CWE-754;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:N';BEST CVSS score: '2.5';DESCR 'The drm/msm IOMMU mapping path used an unsigned size_t variable for the return value of iommu_map_sgtable even though the API can return negative error codes. A negative error can be converted into a large positive value and the original failure reason is lost, causing incorrect error handling in the GPU mapping path. For the CVSS the PR:L is used in the conservative scoring because triggering would require a local process that can exercise the drm/msm GPU or DRM mapping interface. The issue is not network reachable. Impact appears limited to failed GPU mapping operations or limited local availability impact in error paths, with no evidence of memory corruption, information disclosure, or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 1) SKIP CVE-2026-64153 UNKNOWN SKIP No affected files built, so skip this CVE NO - - unknown MAYBE WARNONLY SIMPLEFIX HARDWARE LINUS - - 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: * `+0 WARN_ON continuation / error handling concern` The patch fixes incorrect handling of a negative `iommu_map_sgtable()` return value and avoids WARN-style behavior. The patch does not show a later Oops, UAF, OOB access, double free, stale pointer use, or corruption sink. * `+0 no demonstrated memory corruption` The signedness bug can convert a negative error into a large unsigned value, but the shown caller still returns failure when `ret != len`. There is no evidence that the large value is used as a copy length, allocation size, array index, DMA length, or object selector. * `+0 no demonstrated confidentiality or integrity impact` The failure path appears to lose the original error code and return `-EINVAL`, not expose data or modify protected state. * `-1 rare / hardware-specific path` The affected code is specific to the Qualcomm MSM DRM GPU IOMMU mapping path and requires an IOMMU mapping error condition. * `+1 local unprivileged trigger, paranoid only` In some deployments DRM render nodes may be usable by local unprivileged users, so a local process might be able to exercise GPU mapping paths. This is not enough to make the issue actionable because the impact remains limited. No points awarded for: * remote reachability * privilege escalation * generic memory corruption * real lifetime corruption * reliable kernel crash * Dirty-Pipe-like primitive * high-control API bonus * security-boundary bypass ## 3. Reachability analysis The affected path is local and device-specific. A practical trigger would require a process that can use the `drm/msm` GPU interface and can cause `iommu_map_sgtable()` to fail. On many systems DRM render nodes may be exposed to local users, but this still requires local code execution and suitable MSM GPU hardware. Containers or namespaces do not automatically make this more severe unless the DRM device is explicitly passed through. There is no realistic network trigger. Call-site confidence: high, because the changed function and immediate return-value use are visible in the patch. ## 4. Severity interpretation This behaves like a low-risk correctness and error-propagation issue, not an Important-class vulnerability. The theoretical concern is signedness-related error confusion, but the visible code does not convert that confusion into memory corruption, information disclosure, privilege escalation, or a reliable system-wide DoS. The realistic impact is failed GPU mapping behavior or less precise error reporting. ## 5. One-sentence report phrase The drm/msm IOMMU mapping path stored a negative `iommu_map_sgtable()` error in an unsigned variable, causing incorrect error handling, but the visible impact is limited to local GPU mapping failure behavior without demonstrated memory corruption or privilege escalation. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED Reason: no concrete corruption primitive, no remote exposure, no security-boundary bypass, and no reliable crash path is demonstrated by the patch. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/msm: Fix iommu_map_sgtable() return value check and avoid WARN [ Upstream Commit: 3c2cdb7c07f664b77e2a75b50793b845d5742efa Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3c2cdb7c07f664b77e2a75b50793b845d5742efa Changed files: drivers/gpu/drm/msm/msm_iommu.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=3c2cdb7c07f664b77e2a75b50793b845d5742efa ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-64153 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64153 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:N 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).