From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-72257][LOW] ASoC: qcom: q6apm: fix NULL pointer dereference in graph_callback Date: Sun, 16 Aug 2026 00:08:14 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-72257 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: 1 X-AL-KERNEL-Commit: a164e744d8de1c41049bd9a1452a4b6bbf5bd8bc List-Id: CVE: CVE-2026-72257 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: ASoC: qcom: q6apm: fix NULL pointer dereference in graph_callback Commit: a164e744d8de1c41049bd9a1452a4b6bbf5bd8bc Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a164e744d8de1c41049bd9a1452a4b6bbf5bd8bc Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72257 Analysis date: Sun, 16 Aug 2026 00:08:14 -0400 ActionableScore: 2 ActionableScore lower bound: 1 Actionable bucket: Ordinary Moderate / Low-like Manual review required: NO Summary: A local race in Qualcomm q6apm AudioReach handling can let a late DSP buffer done callback dereference a NULL rx or tx buffer pointer after fragment cleanup, causing a kernel crash but not showing a supported UAF or privilege escalation primitive. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72257 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72257 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-2026-72257 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:H';**CWE-476;CWE-362;CWE-703;BEST CVSS score: '4.7';DESCR 'A NULL pointer dereference in the Qualcomm q6apm AudioReach callback can occur when a late DSP buffer done response races with q6apm_free_fragments. The fragment cleanup path frees rx_data.buf or tx_data.buf and sets the pointer to NULL under graph lock, while graph_callback can later acquire the same lock and dereference the NULL buffer pointer to read buf token phys. For the CVSS the PR:L is used because triggering requires a local user or local process that can exercise the audio device or an audio service on an affected Qualcomm platform. The issue is not network reachable and depends on local audio graph activity plus a timing window with a late DSP response. Impact is denial of service via kernel crash. The patch context supports a NULL dereference race rather than a demonstrated UAF or arbitrary write primitive, so confidentiality and integrity impact are not raised.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2) SKIP CVE-2026-72257 UNKNOWN SKIP No affected files built, so skip this CVE NO - - unknown MAYBE OOB LOCK DANGER NULLPTR SIMPLEFIX RACE KERNEL_PANIC_PLUS_UAF HARDWARE PACKET DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=2 ActionableScoreLower=1 ## 1. ActionableScore * Conservative score: 1 * Paranoid score: 2 * Final recommended bucket: **Ordinary Moderate / Low-like** ## 2. Signal breakdown Triggered signals: * Local unprivileged trigger: +1 A local user or local audio service may be able to exercise the affected Qualcomm q6apm audio graph path. * Reliable kernel crash / strong DoS: +1 The commit explicitly describes a NULL pointer dereference at virtual address 0x10, causing a kernel crash. * Firmware-mediated external influence: +1 in paranoid score only The late buffer-done response comes from the DSP side, but this is not equivalent to a network attacker or clearly malicious firmware control. Subtracted signals: * Hard or unreliable race / special timing required: -1 The crash requires a race between q6apm_free_fragments() and a late DSP callback. Not awarded: * Generic memory corruption: +0 The patch supports NULL pointer dereference, not UAF reclaim, OOB write, type confusion, or arbitrary write. * Privilege escalation plausible: +0 No attacker-controlled stale object reuse, callback corruption, overwrite primitive, or refcount takeover is shown. * Confidentiality / Integrity impact: +0 The demonstrated effect is crash only. ## 3. Reachability analysis The bug is local and platform-specific. It requires an affected Qualcomm QDSP6 AudioReach q6apm setup and local activity that creates and tears down audio fragments while a late DSP buffer-done response is delivered. It is not network reachable. Namespaces do not materially improve reachability unless a container or sandbox is allowed to access the relevant audio device or service. The path may be default on affected Qualcomm systems, but it is not a broad generic Linux subsystem exposure. ## 4. Severity interpretation This behaves like an ordinary Moderate or Low-like kernel DoS issue. Theoretical concern is limited because the freed buffer pointer is set to NULL under the same graph lock, and the observed primitive is a NULL dereference after the callback acquires the lock. Realistic exploitation evidence supports availability impact only, not privilege escalation or data disclosure. ## 5. One-sentence report phrase A local race in Qualcomm q6apm AudioReach handling can let a late DSP buffer done callback dereference a NULL rx or tx buffer pointer after fragment cleanup, causing a kernel crash but not showing a supported UAF or privilege escalation primitive. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED This can be auto-closed in normal triage because it is a local, hardware-specific NULL pointer dereference DoS with race timing requirements and no demonstrated memory corruption, confidentiality, integrity, or LPE primitive. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: ASoC: qcom: q6apm: fix NULL pointer dereference in graph_callback Commit: a164e744d8de1c41049bd9a1452a4b6bbf5bd8bc Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a164e744d8de1c41049bd9a1452a4b6bbf5bd8bc Commit description: When q6apm_free_fragments() is called it frees rx_data.buf/tx_data.buf and sets them to NULL under graph->lock. A late DSP buffer-done response can race with this: graph_callback() passes the !graph->ar_graph guard (not yet NULL), acquires the lock, but then dereferences a now-NULL buf pointer to read buf[token].phys, crashing at virtual address 0x10. Add a NULL check for buf inside the mutex-protected section in both the write-done (DATA_CMD_RSP_WR_SH_MEM_EP_DATA_BUFFER_DONE_V2) and read-done (DATA_CMD_RSP_RD_SH_MEM_EP_DATA_BUFFER_V2) handlers and bail out cleanly if buffers have already been freed. This problem is only shown up recently while apr bus was updated to process the commands per service rather from single global queue. Fixes: 5477518 ("ASoC: qdsp6: audioreach: add q6apm support") Cc: Stable@vger.kernel.org Assisted-by: Claude:claude-4-6-sonnet Reported-by: Val Packett Closes: https://lore.kernel.org/all/133ced18-1aa9-475d-80d8-6120678bdde4@packett.cool/ Signed-off-by: Srinivas Kandagatla Link: https://patch.msgid.link/20260616170257.9381-1-srinivas.kandagatla@oss.qualcomm.com Signed-off-by: Mark Brown Signed-off-by: Greg Kroah-Hartman Changed files: sound/soc/qcom/qdsp6/q6apm.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=a164e744d8de1c41049bd9a1452a4b6bbf5bd8bc ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72257 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72257 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: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: 1 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).