From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-99182][LOW] ASoC: SOF: ipc4-topology: Fix shift-out-of-bounds for aggregated ALH capture [ Upstream Date: Fri, 30 Oct 2026 11:36:52 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-99182 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: 0 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: cad63a7798d6a6cac1fc68732595f0a3278ff6f0 List-Id: CVE: CVE-2026-99182 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: ASoC: SOF: ipc4-topology: Fix shift-out-of-bounds for aggregated ALH capture [ Upstream Commit: cad63a7798d6a6cac1fc68732595f0a3278ff6f0 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=cad63a7798d6a6cac1fc68732595f0a3278ff6f0 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99182 Analysis date: Fri, 30 Oct 2026 11:36:52 -0400 ActionableScore: 0 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate Manual review required: NO Summary: A zero channel-distribution step causes an invalid `GENMASK` shift during specialized SOF aggregated capture setup, with no demonstrated memory corruption or security-boundary effect. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-99182 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99182 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-2026-99182 LOW https://www.kernelcve.org/list/?q=CVE-2026-99182 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-1335;CWE-191;CWE-682;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.7';DESCR 'An arithmetic error in SOF IPC4 topology handling makes step zero when a capture stream has fewer channels than the number of aggregated ALH devices. Subtracting one then underflows the unsigned value and supplies GENMASK with an invalid shift exponent, producing a UBSAN shift out of bounds report and potentially preventing correct audio capture setup. For the CVSS the PR:L value is used because a local user or process must reach the ALSA capture setup path, while the required SOF IPC4 and aggregated SoundWire topology is normally configured by the platform. Confidentiality and integrity are N because the affected value forms a channel mask and the code provides no OOB access, UAF, information leak, or write primitive. Availability is L for a warning or failed stream setup, with H only as a worst case on systems configured to panic on kernel warnings. Automated impact decision path. The original SimpleNet classifier selected LOW. The primary LLM estimated paranoid CVSS 4.7 and the production ActionableScore returned 0 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 2.7 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 0) MAYBE WRITE KASAN OOB LEAK HARDWARE - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=0 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=UNKNOWN NamespaceScopedPrivilege=NO ImportantCandidate=NO ManualReview=NO AutoDowngradeAllowed=YES RequiresHostUID0=UNKNOWN AuthorizationDecisionBypass=NO ProtectedResourceImpact=NONE B4PendingReview=NO B4PendingConfirmed=NO 1. ActionableScore * Raw base score: 0. * Conservative score: 0; no floor or cap applies. * Raw paranoid score: 0. * Paranoid score: 0; panic-on-warning is deployment-dependent and does not earn a crash point. * Final recommended bucket: **Ordinary Moderate**:: 2. Signal breakdown * +0 invalid arithmetic/shift: integer division produces `step == 0`, after which `GENMASK(step - 1, 0)` invokes an invalid shift. This is not a heap or slab out-of-bounds access. * +0 warning or failed stream setup: UBSAN reports the shift, but the patch does not establish a reliable host crash. Device-local capture setup failure is insufficient for strong DoS scoring. * No local-unprivileged bonus: ALSA capture-path reachability is plausible, but permissions for the complete topology/stream operation are not shown. * No corruption, UAF, disclosure, authorization bypass, protected-resource modification, arbitrary write, or integrity impact is shown. * B5-R does not apply: there is no heap OOB write, retry-accumulated index, or later consumption of corrupted structured state. * No hardware or privilege penalty was applied because neither rare-hardware status nor host-admin-only triggering is positively established. 3. Reachability analysis The vulnerable path requires SOF IPC4, an aggregated ALH/SoundWire topology, and a capture stream with fewer channels than aggregated devices. Platform firmware/topology normally supplies the aggregation, while a local process may initiate capture; however, the evidence does not establish the complete caller permissions. Thus host-admin need and host UID 0 need remain unknown. No namespace capability or remote path is involved, and no race or retry sequence is shown. 4. Primitive and severity reading The exact defect is an unsigned underflow feeding an invalid shift exponent into `GENMASK`. It is an invalid-state/availability issue, classified CLASS_C, not an OOB memory operation. The demonstrated outcome is a UBSAN warning and potentially incorrect or failed audio capture setup. Kernel panic requires an additional panic-on-warning policy and is not established. There is no meaningful exploit leverage past that behavior, so this is not an Important candidate and automatic downgrade is allowed. 5. One-sentence report phrase A zero channel-distribution step causes an invalid `GENMASK` shift during specialized SOF aggregated capture setup, with no demonstrated memory corruption or security-boundary effect. 6. Manual review advice NO MANUAL CHECK NEEDED The patch and commit identify a bounded arithmetic/shift defect without a security primitive. 7. Call-site confidence Call-site confidence: medium ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: ASoC: SOF: ipc4-topology: Fix shift-out-of-bounds for aggregated ALH capture [ Upstream Commit: cad63a7798d6a6cac1fc68732595f0a3278ff6f0 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=cad63a7798d6a6cac1fc68732595f0a3278ff6f0 Changed files: sound/soc/sof/ipc4-topology.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=cad63a7798d6a6cac1fc68732595f0a3278ff6f0 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-99182 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99182 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: 0 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).