From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-68351][MODERATE 7.0] wifi: carl9170: bound memcpy length in cmd callback to prevent OOB read [ Upstream Date: Mon, 10 Aug 2026 17:56:33 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-68351 X-AL-KERNEL-Priority: MODERATE 7.0 X-AL-KERNEL-Severity: MODERATE 7.0 X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: YES X-AL-KERNEL-ActionableScore: 6 X-AL-KERNEL-ActionableScore-Lower: 4 X-AL-KERNEL-Commit: f74e34e66379e487a09009a4f2d42470051672bd List-Id: CVE: CVE-2026-68351 Priority: MODERATE 7.0 AL-KERNEL base severity: MODERATE KPANIC flag: YES Patch: wifi: carl9170: bound memcpy length in cmd callback to prevent OOB read [ Upstream Commit: f74e34e66379e487a09009a4f2d42470051672bd Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f74e34e66379e487a09009a4f2d42470051672bd Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68351 Analysis date: Mon, 10 Aug 2026 17:56:33 -0400 ActionableScore: 6 ActionableScore lower bound: 4 Actionable bucket: Actionable Moderate at minimum Manual review required: YES Summary: A firmware-controlled length in `carl9170_cmd_callback()` could cause `memcpy()` to write past `ar->readbuf`, allowing a malicious or compromised carl9170 USB WiFi device or firmware to trigger kernel memory corruption and likely DoS, with theoretical privilege-escalation concern requiring manual review. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68351 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68351 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 7.0 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-2026-68351 MODERATE CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H';*CWE-787;CWE-125;*CWE-20;CWE-119;Other CVSS 'AV:P/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H';BEST CVSS score: '6.8';DESCR 'carl9170_cmd_callback() copied firmware response data into ar readbuf using len from the device without bounding the copy by ar readlen. A malformed or malicious command response with len larger than the expected read buffer can make memcpy write past readbuf and create a kernel memory corruption condition. For the CVSS the PR:N is used because the attacker does not need a local user account on the host when the attack is modeled as a malicious or compromised USB WiFi device or firmware. The practical attack surface is not the public network and is not directly reachable through normal WiFi packet traffic based on the patch context. Exploitation usually requires control of the attached device, firmware, or a USB emulation path. Impact is at least denial of service via kernel crash and in worst case may allow confidentiality or integrity impact due to kernel memory corruption.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 5) YES REMOTE OOB SIMPLEFIX NETWORK LINUS KPANIC NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=6 ActionableScoreLower=4 ## 1. ActionableScore * Conservative score: 4 * Paranoid score: 6 * Final recommended bucket: **Actionable Moderate at minimum**:: ## 2. Signal breakdown Conservative signals: * Firmware-mediated external influence: +1 `len` comes from the device firmware response, so a malicious or compromised carl9170 USB WiFi device or firmware can influence the copy length. * Generic memory corruption, strong corruption primitive: +2 The old code used `memcpy(ar->readbuf, buffer + 4, len - 4)` without bounding the destination size by `ar->readlen`. If `len - 4` exceeds `ar->readlen`, this is a kernel heap out-of-bounds write into memory after `readbuf`, not merely a harmless OOB read. * Reliable kernel crash / strong DoS: +1 A malformed response can plausibly corrupt adjacent kernel memory and crash the driver or kernel. * Privileged kernel/device-management memory corruption path: +1 The corruption occurs in a trusted wireless USB driver command-response path fed by firmware/device data. * Physical-only or rare hardware-only condition: -2 The realistic attacker model requires a malicious attached USB WiFi device, compromised firmware, USB emulation, or similar device-level control. This is not remotely reachable over normal WiFi traffic. * Weak LPE concern: +1 Kernel heap OOB write gives a theoretical escalation concern, but no reclaim, object targeting, function-pointer control, or reliable exploitation primitive is demonstrated by the patch. Paranoid additions: * Confidentiality impact plausible: +1 Because this is kernel memory corruption and the copy source/destination are in kernel memory, limited disclosure or readback side effects cannot be fully excluded without deeper call-site review. * Integrity impact plausible: +1 An OOB write into adjacent kernel heap memory can corrupt kernel state. Practical control is uncertain, but integrity impact is defensible for paranoid triage. Paranoid score result: 6. ## 3. Reachability analysis The bug is triggerable through firmware or device-supplied command responses in the `carl9170` wireless USB driver. It is not a normal network-reachable bug and should not be treated as AV:N style remote packet parsing. The realistic attacker needs control over the attached carl9170 device, its firmware, a malicious USB device, or a USB emulation path. No local Linux user account is required in the malicious-device model, but physical/device adjacency is required. Namespaces and containers do not materially lower the trigger requirements because the vulnerable input is supplied by the hardware/firmware path, not by a namespaced userspace API. The affected driver is hardware-specific and not a broad default kernel path. Exposure is therefore limited to systems using this legacy Atheros carl9170 USB WiFi hardware or equivalent emulated device behavior. Call-site confidence: high. The patch directly shows the vulnerable `memcpy()` call and the added bound using `min_t(u32, len - 4, ar->readlen)`. ## 4. Severity interpretation This is stronger than an ordinary Moderate because the patch fixes a firmware-controlled copy length that can exceed the allocated destination buffer. That is a concrete kernel memory corruption primitive. It is not a clear Important by default because exploitation requires a malicious or compromised device/firmware path, target selection is not demonstrated, and there is no evidence of reliable object replacement, callback control, or arbitrary write. Realistic impact is likely kernel crash or device-driver corruption. Paranoid triage should still keep it actionable because firmware-fed OOB writes in kernel drivers can be underestimated. ## 5. One-sentence report phrase A firmware-controlled length in `carl9170_cmd_callback()` could cause `memcpy()` to write past `ar->readbuf`, allowing a malicious or compromised carl9170 USB WiFi device or firmware to trigger kernel memory corruption and likely DoS, with theoretical privilege-escalation concern requiring manual review. ## 6. Manual review recommendation MANUAL CHECK REQUIRED Reason: the patch fixes a concrete kernel heap OOB write in a firmware-fed driver path. Even though exposure is limited and not network-reachable, the memory corruption primitive is real enough to avoid auto-close. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: wifi: carl9170: bound memcpy length in cmd callback to prevent OOB read [ Upstream Commit: f74e34e66379e487a09009a4f2d42470051672bd Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f74e34e66379e487a09009a4f2d42470051672bd Changed files: drivers/net/wireless/ath/carl9170/rx.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=f74e34e66379e487a09009a4f2d42470051672bd ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68351 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68351 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:P/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H The Best / paranoid CVSS vector: AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H The Best / paranoid CVSS score: 6.8 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: 4 Paranoid ActionableScore: 6 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: YES Published priority for this report (same as in Subject): MODERATE 7.0 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).