From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-99149][LOW] drm/amdgpu: fix GEM object leak on ENOMEM in userptr ioctl Date: Wed, 28 Oct 2026 23:07:04 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-99149 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: unknown X-AL-KERNEL-Commit: 64a6d40156ae98caafc922c6d79fe202b0acd836 List-Id: CVE: CVE-2026-99149 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: drm/amdgpu: fix GEM object leak on ENOMEM in userptr ioctl Commit: 64a6d40156ae98caafc922c6d79fe202b0acd836 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=64a6d40156ae98caafc922c6d79fe202b0acd836 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99149 Analysis date: Wed, 28 Oct 2026 23:07:04 -0400 ActionableScore: 2 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate Manual review required: NO Summary: AMDGPU userptr allocation failure can leak a GEM object, VM-root reference, and MMU-notifier registration, with only resource-retention impact established. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-99149 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99149 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-2026-99149 LOW https://www.kernelcve.org/list/?q=CVE-2026-99149 CHECK WITH IMPACT FROM ORIG NN LOW | AEGIS IMPACT LOW AEGIS_AS=1 LEGACY=LOW RESULT=SAME (final reconciliation agrees; DECISION: both 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-401;*CWE-772;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.7';DESCR 'amdgpu_gem_userptr_ioctl returned directly when amdgpu_hmm_range_alloc failed, bypassing cleanup of the newly created GEM object, its VM root parent reference, and its MMU notifier registration. The demonstrated primitive is persistent resource retention rather than memory corruption because the leaked object remains allocated and no stale freed pointer is established. For the CVSS the PR:L value reflects that a local process needs access to the AMDGPU DRM device and must issue the userptr ioctl. AC:H reflects the need to make the specific range allocation fail after object setup. Availability impact is normally low, while sustained and repeatable failures under memory pressure could potentially contribute to broader resource exhaustion. There is no direct network attack path and no supported confidentiality or integrity impact. Automated impact decision path. The original SimpleNet classifier selected LOW. The primary LLM estimated paranoid CVSS 4.7 and the production ActionableScore returned 2 with recommendation Ordinary Moderate. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. No severity changing production threshold or specialist override was recorded. The legacy KP specialist has no review artifact for this run. The legacy FD or DH downgrade specialist has no review artifact for this run. The independent weaker Aegis shadow evaluated CVSS 2.5 and ActionableScore 1 with primitive class CLASS_C and manual review REQUIRED. Its independently reconciled impact was LOW. The shadow agreed with the final production impact and aggregation did not change that impact. The final reported impact is LOW.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2) MAYBE NOMEMCHK SIMPLEFIX LEAK ERRORPATH HARDWARE - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=2 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=NO NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=NO ManualReview=NO AutoDowngradeAllowed=YES RequiresHostUID0=NO AuthorizationDecisionBypass=NO ProtectedResourceImpact=NONE B4PendingReview=NO B4PendingConfirmed=NO 1. ActionableScore * Raw base score: 2. * Conservative score: 2; no floor or cap applied. * Raw paranoid score: 2. * Paranoid score: 2; potential exhaustion is not sufficiently demonstrated for another point. * Final recommended bucket: **Ordinary Moderate**:: 2. Signal breakdown * +1 — Concrete persistent kernel resource/reference leak: allocation failure returned directly after creation of the GEM object, VM-root parent reference, and MMU-notifier registration, bypassing their normal cleanup. * +1 — Local below-host-admin trigger: the supplied evidence grounds the path in a userptr DRM ioctl available to a local process with AMDGPU device access. * +0 — No reliable kernel crash or strong host-wide exhaustion is shown. Repeated ENOMEM failures might accumulate resources, but material accumulation and host-wide availability impact remain unproven. * +0 — No UAF, stale freed pointer, OOB access, shared-backing overwrite, authorization bypass, or corrupted-state consumer is shown. * +0 — NEW52/B5-R does not apply: there is no retry-accumulated heap OOB write. * +0 — No confidentiality, integrity, LPE, or arbitrary-write effect is supported. 3. Reachability analysis A local process with access to the AMDGPU DRM device can issue the userptr ioctl. This is below host-administrator privilege according to the supplied PR:L evidence and does not require host UID 0. Triggering the precise failure requires `amdgpu_hmm_range_alloc()` to return NULL after object setup, likely through memory pressure, but no narrow race is shown. Namespace capability scope and any device-delegation details are unresolved; they are unnecessary to establish the supplied local device-access path. 4. Primitive and severity reading The exact defect is a missing error-unwind path causing persistent retention of an active GEM object and associated references/registration. The object is not freed, so this is neither a UAF nor post-lifetime corruption. CLASS_C reflects resource-retention/availability behavior without a separately useful corruption primitive. Important-grade leverage is absent, and ordinary Moderate handling is appropriate. 5. One-sentence report phrase AMDGPU userptr allocation failure can leak a GEM object, VM-root reference, and MMU-notifier registration, with only resource-retention impact established. 6. Manual review advice NO MANUAL CHECK NEEDED The patch and commit establish a bounded resource-cleanup defect without an unresolved corruption or security-boundary primitive. 7. Call-site confidence Call-site confidence: high ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/amdgpu: fix GEM object leak on ENOMEM in userptr ioctl Commit: 64a6d40156ae98caafc922c6d79fe202b0acd836 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=64a6d40156ae98caafc922c6d79fe202b0acd836 Commit description: When amdgpu_hmm_range_alloc() fails amdgpu_gem_userptr_ioctl() returns -ENOMEM right away and skips the cleanup every other error path goes through. The GEM object, the bo->parent reference on the VM root and the MMU notifier registration are all left behind. Use release_object here, not user_pages_done, range is still NULL at this point. Fixes: e095b55 ("drm/amdgpu: use user provided hmm_range buffer in amdgpu_ttm_tt_get_user_pages") Signed-off-by: Perry Yuan Reviewed-by: Christian König Signed-off-by: Alex Deucher (cherry picked from commit bbe739e407a542073ec1a7872b14843566b4919e) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman Changed files: drivers/gpu/drm/amd/amdgpu/amdgpu_gem.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=64a6d40156ae98caafc922c6d79fe202b0acd836 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-99149 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99149 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: unknown 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).