From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-98779][LOW] drm/amdgpu: fix ACP MFD device leak on init failure Date: Sat, 24 Oct 2026 10:18:07 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-98779 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: unknown X-AL-KERNEL-Commit: 2b9a53940a2bc063ea4cd09ee49220a503a0170c List-Id: CVE: CVE-2026-98779 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: drm/amdgpu: fix ACP MFD device leak on init failure Commit: 2b9a53940a2bc063ea4cd09ee49220a503a0170c Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2b9a53940a2bc063ea4cd09ee49220a503a0170c Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98779 Analysis date: Sat, 24 Oct 2026 10:18:07 -0400 ActionableScore: 1 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate Manual review required: NO Summary: ACP initialization failures can leave registered child devices and power-domain attachments unreleased, causing a bounded device-resource leak without demonstrated memory corruption or security-boundary impact. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-98779 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98779 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-2026-98779 LOW https://www.kernelcve.org/list/?q=CVE-2026-98779 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:H/UI:N/S:U/C:N/I:N/A:L';*CWE-772;CWE-404;CWE-459;BEST CVSS score: '1.9';DESCR 'ACP initialization can leave MFD child platform devices registered when power domain attachment, hardware reset, or clock initialization fails after mfd_add_devices succeeds. The demonstrated primitive is persistent retention of a finite set of device objects and possibly stale power domain attachments, not memory corruption, information disclosure, or an arbitrary write. For the CVSS the PR:H value reflects that reliably forcing device reprobe or low level AMD GPU initialization normally requires administrative device management privileges. The failure also depends on a post registration attachment error or hardware timeout, so AC:H is appropriate. Direct network reachability and reliable unprivileged resource exhaustion are not established, and the supported impact is limited availability degradation in the ACP driver path. Automated impact decision path. The original SimpleNet classifier selected LOW. The primary LLM estimated paranoid CVSS 1.9 and the production ActionableScore returned 1 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 1.9 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 1) MAYBE SIMPLEFIX LEAK HARDWARE - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=1 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=UNKNOWN NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=NO ManualReview=NO AutoDowngradeAllowed=YES RequiresHostUID0=UNKNOWN AuthorizationDecisionBypass=NO ProtectedResourceImpact=NONE B4PendingReview=NO B4PendingConfirmed=NO 1. ActionableScore * Raw base score: 1. * Conservative score: 1; no floor or cap applied. * Raw paranoid score: 1. * Paranoid score: 1; no stronger technically supported consequence. * Final recommended bucket: **Ordinary Moderate**:: 2. Signal breakdown * +1 Concrete persistent kernel resource leak: after `mfd_add_devices()` succeeds, several failure branches free ACP allocations without unregistering the already registered child platform devices. The patch adds `mfd_remove_devices()` and power-domain detachment. * No privilege penalty: administrative device-management access is plausible, but the supplied evidence does not positively establish the complete trigger privilege. * No timing penalty: reset/clock timeout is a failure condition, but no attacker-driven narrow race is shown. * No crash or availability point: only finite retained device objects and stale attachments are supported; host-wide exhaustion or failure is not demonstrated. * No UAF, OOB write, double release, authorization bypass, shared-backing write, disclosure, or protected-state corruption is shown. * B5-R does not apply: there is no retry-accumulated heap OOB write or later consumption of corrupted state. 3. Reachability analysis The vulnerable path is GPU ACP hardware initialization after child registration. Reliably inducing reprobe or low-level initialization failure may require host device-management authority or hardware failure, but the complete attacker-controlled trigger is not established. No namespace-scoped capability path, ordinary-user interface, special retry control, or remote reachability is shown. 4. Primitive and severity reading The exact defect is failure-path resource cleanup omission: registered MFD children and possible power-domain attachments survive failed initialization. This is passive retained kernel/device state, classified CLASS_C rather than memory corruption or a lifetime-invalid stale use. The demonstrated effect is a bounded device-object leak and possible ACP availability degradation. Important-grade leverage is absent, so automatic downgrade is allowed. 5. One-sentence report phrase ACP initialization failures can leave registered child devices and power-domain attachments unreleased, causing a bounded device-resource leak without demonstrated memory corruption or security-boundary impact. 6. Manual review advice NO MANUAL CHECK NEEDED The patch and commit establish only a constrained initialization resource leak. 7. Call-site confidence Call-site confidence: high ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/amdgpu: fix ACP MFD device leak on init failure Commit: 2b9a53940a2bc063ea4cd09ee49220a503a0170c Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2b9a53940a2bc063ea4cd09ee49220a503a0170c Commit description: acp_hw_init() registers ACP child devices with mfd_add_devices() before attaching them to the ACP power domain and initializing the hardware. If attaching a child to the power domain fails, or if the ACP reset or clock enable operation times out, the failure path frees only the source cell, resource, and platform-data allocations. The child platform devices already registered by mfd_add_devices() remain registered and are never released. Remove the children from the power domain and unregister the MFD devices on failures that occur after mfd_add_devices() succeeds. Keep mfd_add_devices() failures on the existing cleanup path since the MFD core already rolls back partially registered children itself. The issue was identified by a static analysis tool I developed and confirmed by manual review. Fixes: 2503032 ("drm/amd: add pm domain for ACP IP sub blocks") Signed-off-by: Guangshuo Li Signed-off-by: Alex Deucher (cherry picked from commit 63da68d ) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman Changed files: drivers/gpu/drm/amd/amdgpu/amdgpu_acp.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=2b9a53940a2bc063ea4cd09ee49220a503a0170c ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-98779 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98779 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: Not available The Best / paranoid CVSS vector: AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L The Best / paranoid CVSS score: 1.9 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: 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).