From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-72304][MODERATE REGULAR] ASoC: SOF: ipc4-control: Fix TOCTOU in sof_ipc4_bytes_put Date: Sat, 15 Aug 2026 05:34:12 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-72304 X-AL-KERNEL-Priority: MODERATE REGULAR X-AL-KERNEL-Severity: MODERATE REGULAR X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 4 X-AL-KERNEL-ActionableScore-Lower: 3 X-AL-KERNEL-Commit: 266f936db83aee6ca6473bbb06259bda52bf4fc3 List-Id: CVE: CVE-2026-72304 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: ASoC: SOF: ipc4-control: Fix TOCTOU in sof_ipc4_bytes_put Commit: 266f936db83aee6ca6473bbb06259bda52bf4fc3 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=266f936db83aee6ca6473bbb06259bda52bf4fc3 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72304 Analysis date: Sat, 15 Aug 2026 05:34:12 -0400 ActionableScore: 4 ActionableScore lower bound: 3 Actionable bucket: Borderline Moderate, manual review recommended Manual review required: YES Summary: A local ALSA control user can trigger a TOCTOU style size mismatch in sof_ipc4_bytes_put, causing the SOF IPC4 bytes control path to copy truncated or stale data into the kernel control buffer with limited integrity and possible limited confidentiality impact. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72304 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72304 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: MODERATE REGULAR Manual review required: YES A detailed explanation of the methodology and priority rules is included at the end of this message. ====================================================================== AL-KERNEL CLASSIFICATION RESULT ====================================================================== CVE-2026-72304 MODERATE CHECK WITH IMPACT FROM ORIG NN LOW Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L';CWE-367;*CWE-20;CWE-130;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L';BEST CVSS score: '5.3';DESCR 'A TOCTOU style size validation bug in ASoC SOF IPC4 bytes controls occurs because sof_ipc4_bytes_put uses the old stored data size to validate and choose the memcpy length instead of the incoming sof_abi_hdr size from ucontrol. A local process with access to the ALSA control interface can submit bytes control data with a different header size, which can truncate valid input or copy stale bytes into the kernel control buffer and then into the SOF control path. For the CVSS the PR:L because reliable triggering requires local code execution and access to the sound control device or an equivalent service account, but not full administrator privileges in common desktop or audio group deployments. The issue is not network reachable. Impact is mainly limited integrity and availability of the audio control path, with a paranoid limited confidentiality concern if stale bytes become observable through later control reads or firmware interactions.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline Moderate, manual review recommended (with actual score 4) YES SIMPLEFIX HARDWARE INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=4 ActionableScoreLower=3 ## 1. ActionableScore * Conservative score: 3 * Paranoid score: 4 * Final recommended bucket: **Borderline Moderate, manual review recommended**:: ## 2. Signal breakdown Conservative signals: * Local unprivileged trigger: +1 A local process with access to the ALSA control device can likely reach the bytes control put path. This is often available to desktop users or audio group users, not necessarily full root. * Constrained kernel buffer overwrite / logical buffer state corruption: +1 The memcpy target is a bounded SOF control buffer, but the copied length is derived from stale stored state rather than the incoming header. This can copy the wrong logical payload length, causing truncation or stale bytes in the control buffer. * Integrity impact plausible: +1 The attacker can influence SOF IPC4 control state inconsistently with the declared incoming size. This is a limited integrity impact on audio control or firmware-facing control data. Paranoid additional signal: * Confidentiality impact plausible: +1 If stale bytes copied into the control buffer can later be observed via control reads or firmware interactions, limited data exposure is possible. This is not a strong info leak primitive, so C:L only. Not awarded: * No generic strong memory corruption. The patch does not show OOB write, UAF, double free, type confusion, refcount abuse, or arbitrary write. * No strong DoS. The commit does not show kernel panic, Oops, firmware crash, or persistent system-wide failure. * No privilege escalation signal. There is no reclaim, callback control, object confusion, or attacker-controlled kernel memory corruption primitive. * No network reachability. ## 3. Reachability analysis The trigger is local through the ALSA/SOF bytes control interface. In typical systems this may be reachable by users with audio device access, desktop session access, or an audio service account, so PR:L is more appropriate than PR:H for practical triage. Containers and sandboxes only matter if the sound control device is passed through to them. The path is not network reachable and depends on systems using SOF IPC4-capable audio hardware and exposing the relevant control. Call-site confidence: medium. The changed function and immediate copy behavior are visible, but broader get paths and firmware-side effects are not included in the supplied patch. ## 4. Severity interpretation This behaves like a borderline or actionable Moderate validation bug, not an Important-class kernel memory corruption issue. The realistic impact is limited corruption of SOF control state, possible stale data propagation, and possible local audio/control malfunction. The theoretical concern is limited C/I/A impact through stale bytes or firmware-facing state, but the patch does not support LPE, arbitrary kernel memory corruption, or reliable kernel crash. ## 5. One-sentence report phrase A local ALSA control user can trigger a TOCTOU style size mismatch in sof_ipc4_bytes_put, causing the SOF IPC4 bytes control path to copy truncated or stale data into the kernel control buffer with limited integrity and possible limited confidentiality impact. ## 6. Manual review recommendation MANUAL CHECK RECOMMENDED Reason: the issue is not strong memory corruption, but it is a local user-reachable size validation bug in a firmware-facing control path, with possible stale-data behavior and limited C/I impact that should not be blindly auto-closed without confirming exposure and read-back behavior. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: ASoC: SOF: ipc4-control: Fix TOCTOU in sof_ipc4_bytes_put Commit: 266f936db83aee6ca6473bbb06259bda52bf4fc3 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=266f936db83aee6ca6473bbb06259bda52bf4fc3 Commit description: In sof_ipc4_bytes_put(), the copy size is derived from the old data->size in the buffer rather than the incoming new data's size field from ucontrol. If the new data has a different size, the copy uses the wrong length: it may truncate valid data or copy stale bytes. Fix by validating and using the incoming data's sof_abi_hdr.size from ucontrol before copying. Fixes: a062c88 ("ASoC: SOF: ipc4-control: Add support for bytes control get and put") Cc: stable@vger.kernel.org Signed-off-by: Peter Ujfalusi Reviewed-by: Liam Girdwood Reviewed-by: Bard Liao Link: https://patch.msgid.link/20260609083458.31193-2-peter.ujfalusi@linux.intel.com Signed-off-by: Mark Brown Signed-off-by: Greg Kroah-Hartman Changed files: sound/soc/sof/ipc4-control.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=266f936db83aee6ca6473bbb06259bda52bf4fc3 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72304 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72304 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:L/PR:L/UI:N/S:U/C:N/I:L/A:L The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L The Best / paranoid CVSS score: 5.3 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: 3 Paranoid ActionableScore: 4 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: MODERATE KPANIC detected for this report: NO Published priority for this report (same as in Subject): MODERATE REGULAR 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).