From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-74411][MODERATE REGULAR] wifi: rtw89: Correct data type for scan index to avoid infinite loop [ Upstream Date: Sat, 15 Aug 2026 13:01:32 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-74411 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: 3 X-AL-KERNEL-ActionableScore-Lower: 2 X-AL-KERNEL-Commit: 966fbed4b4463fbcb49c5becf3f86eae776861bd List-Id: CVE: CVE-2026-74411 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: wifi: rtw89: Correct data type for scan index to avoid infinite loop [ Upstream Commit: 966fbed4b4463fbcb49c5becf3f86eae776861bd Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=966fbed4b4463fbcb49c5becf3f86eae776861bd Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74411 Analysis date: Sat, 15 Aug 2026 13:01:32 -0400 ActionableScore: 3 ActionableScore lower bound: 2 Actionable bucket: Borderline Moderate, manual review recommended Manual review required: YES Summary: A u8 loop counter in the rtw89 6 GHz scan path can wrap when processing more than 255 scan parameters, causing an infinite loop, CPU soft lockup, and possible kernel panic on affected Wi-Fi systems. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-74411 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74411 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-2026-74411 MODERATE CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H';CWE-190;*CWE-835;**CWE-400;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.3';DESCR 'A scan index wraparound in the rtw89 6 GHz scan path can cause an infinite loop when the number of 6 GHz scan parameters exceeds 255. The loop counter was stored in an 8 bit type, so it can wrap and keep revalidating values instead of reaching the real limit. This can result in a CPU soft lockup in rtw89_hw_scan_add_chan_ax and may lead to a kernel panic, causing denial of service. For the CVSS the PR:N is used in the paranoid adjacent attack model because a nearby attacker controlling crafted Wi-Fi beacon or RNR data may not need local privileges on the victim if the victim performs 6 GHz scanning. The issue is adjacent network reachable rather than Internet reachable and exploitation depends on a suitable Wi-Fi environment with enough scan parameters. Impact is availability only, with no supported evidence of memory corruption, information disclosure, or privilege escalation.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline Moderate, manual review recommended (with actual score 3) YES REMOTE DEADLOCK DANGER NETWORK KERNEL_PANIC_PLUS_UAF HARDWARE LINUS DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=3 ActionableScoreLower=2 ## 1. ActionableScore * Conservative score: 2 * Paranoid score: 3 * Final recommended bucket: **Borderline Moderate, manual review recommended** ## 2. Signal breakdown * Adjacent network-triggerable / wireless external influence: +2 in paranoid scoring. A nearby attacker may be able to influence 6 GHz RNR or scan parameters through Wi-Fi management-frame environment, but this is adjacent RF exposure, not Internet-reachable. * Local unprivileged trigger: +1 in conservative scoring. A local user or desktop network service may initiate Wi-Fi scanning, depending on policy and user permissions. * Reliable kernel crash / strong DoS: +1. The commit shows a reproducible CPU soft lockup lasting more than 20 seconds and leading to panic. * Hard or special triggering conditions: -1. Triggering requires 6 GHz scan state with more than 255 parameters and likely a specific RF/device environment. * No memory corruption signal: +0. The patch only changes the loop counter type from u8 to u32. It supports integer wraparound and infinite loop, not UAF, OOB write, type confusion, or LPE. * Availability impact realistic: +0 additional. Crash impact is already counted as strong DoS, and there is no persistent corruption or broader availability effect beyond panic. * Driver and hardware specificity: conservative downgrade considered. rtw89 is hardware-specific, but Wi-Fi scanning is a common user-visible path, so I do not apply a strong rare-subsystem penalty. ## 3. Reachability analysis A local user may be able to trigger scanning directly or indirectly through normal Wi-Fi management components, depending on distro policy and NetworkManager or wpa_supplicant integration. A nearby attacker may be able to influence the scan input indirectly through crafted or dense 6 GHz RNR information, but this requires adjacent wireless presence and a compatible rtw89 device. Containers do not materially improve reachability unless they can access host Wi-Fi control paths. The affected path is not Internet-reachable and is limited to systems using the Realtek rtw89 driver with 6 GHz scan support. ## 4. Severity interpretation This behaves like an actionable DoS-oriented Moderate, not an Important memory-corruption issue. The realistic impact is kernel soft lockup and panic. Theoretical LPE is not supported by the patch because the fix addresses an integer-width loop counter bug, with no evidence of stale object reuse, overwrite, UAF, or attacker-controlled kernel memory corruption. ## 5. One-sentence report phrase A u8 loop counter in the rtw89 6 GHz scan path can wrap when processing more than 255 scan parameters, causing an infinite loop, CPU soft lockup, and possible kernel panic on affected Wi-Fi systems. ## 6. Manual review recommendation MANUAL CHECK REQUIRED Reason: no memory corruption or LPE is indicated, but the bug is plausibly adjacent-wireless-triggerable and causes kernel panic, so it should not be auto-closed without confirming real-world 6 GHz RNR triggerability and affected product exposure. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: wifi: rtw89: Correct data type for scan index to avoid infinite loop [ Upstream Commit: 966fbed4b4463fbcb49c5becf3f86eae776861bd Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=966fbed4b4463fbcb49c5becf3f86eae776861bd Changed files: drivers/net/wireless/realtek/rtw89/fw.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=966fbed4b4463fbcb49c5becf3f86eae776861bd ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-74411 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74411 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:H The Best / paranoid CVSS vector: AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H 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: 2 Paranoid ActionableScore: 3 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).