From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-74366][MODERATE REGULAR] wifi: ath12k: fix NULL deref in change_sta_links for unready link [ Upstream Date: Sun, 16 Aug 2026 01:06:36 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-74366 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: cfcea221db933295bf2cd75a7f80d441c7a51e28 List-Id: CVE: CVE-2026-74366 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: wifi: ath12k: fix NULL deref in change_sta_links for unready link [ Upstream Commit: cfcea221db933295bf2cd75a7f80d441c7a51e28 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=cfcea221db933295bf2cd75a7f80d441c7a51e28 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74366 Analysis date: Sun, 16 Aug 2026 01:06:36 -0400 ActionableScore: 4 ActionableScore lower bound: 3 Actionable bucket: Borderline, manual review recommended / Actionable Moderate candidate Manual review required: YES Summary: An ath12k WiFi MLO state handling bug can leave an uncreated link in `links_map`, allowing later station removal or key installation paths to dereference a NULL `arvif->ar` and crash the kernel from adjacent WiFi conditions. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-74366 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74366 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-2026-74366 MODERATE CHECK WITH IMPACT FROM ORIG NN LOW 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-476;CWE-754;CWE-665;Other CVSS 'AV:A/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H';BEST CVSS score: '5.3';DESCR 'A NULL pointer dereference in the ath12k WiFi MLO station link path can occur because ath12k_mac_op_change_sta_links() may add an unready link to the station links_map before verifying that the related arvif was created. If channel assignment fails at the mac80211 level, for example due to combinations check, DFS, or no available radio, the vdev is not created and arvif ar remains NULL. Later operations such as station removal on disconnect or PTK key installation can iterate links_map and dereference the broken link, causing a kernel crash (DoS). For the CVSS the PR:N is used because an attacker does not need privileges on the victim host if the bug is triggered through WiFi association behavior. The issue is adjacent network reachable rather than Internet reachable, because the attacker generally needs WiFi range or control of the access point involved in the connection. Impact is denial of service only, with no clear UAF, OOB write, information leak, or privilege escalation primitive visible from the code path.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline, manual review recommended / Actionable Moderate candidate (with actual score 4) YES REMOTE DANGER NULLPTR ERRORPATH NETWORK KERNEL_PANIC_PLUS_UAF LINUS DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 YES NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=4 ActionableScoreLower=3 ## 1. ActionableScore * Conservative score: 3 * Paranoid score: 4 * Final recommended bucket: **Borderline, manual review recommended / Actionable Moderate candidate**:: ## 2. Signal breakdown Triggered signals: * Remote reachable / network-triggerable: +2 The trigger is not Internet remote, but it is realistically adjacent-network reachable through WiFi association or AP-controlled connection behavior. * Reliable kernel crash / strong DoS: +1 The commit provides concrete NULL dereference crash traces in `ath12k_mac_ml_station_remove()` and `ath12k_mac_op_set_key()`. * Availability impact realistic: +1 in paranoid score only Once the broken link is inserted into `links_map`, later normal operations such as disconnect or PTK key installation can crash the kernel. Subtractors: * Hard or unreliable race / special triggering conditions: -1 The trigger requires a specific MLO link setup failure path, such as channel validation failure, DFS, combinations check, or no available radio. Not awarded: * Generic memory corruption: +0 This is a NULL pointer dereference, not UAF, OOB write, double free, refcount misuse, or type confusion. * Privilege escalation plausible: +0 No reclaim, overwrite, callback control, object confusion, or attacker-controlled memory reuse is shown. * Confidentiality / integrity impact: +0 The patch and call paths support DoS only. ## 3. Reachability analysis The bug can plausibly be triggered by an adjacent WiFi attacker or malicious AP that can influence MLO association/link setup behavior. The victim does not need local attacker code execution, so host-side privileges are not required for the network-triggered scenario. This is not a generic Internet-reachable bug because the attacker normally needs WiFi range or control of the AP/network involved in association. The affected path depends on ath12k hardware and WiFi MLO behavior, so exposure is narrower than core networking. However, the crash occurs in normal mac80211/ath12k station management paths after the invalid link state is created. Call-site confidence: high. The commit includes the relevant changed function and two concrete downstream crash paths. ## 4. Severity interpretation This behaves like an actionable Moderate rather than an Important-class vulnerability. The realistic impact is kernel availability loss through NULL dereference. Theoretical escalation is not supported because the bug leaves an invalid link in `links_map` and later dereferences `arvif->ar`, but does not show memory reuse, writable stale object access, or an arbitrary write primitive. Manual review is still warranted because the bug is adjacent-network reachable and can crash the kernel without local privileges on the victim. ## 5. One-sentence report phrase An ath12k WiFi MLO state handling bug can leave an uncreated link in `links_map`, allowing later station removal or key installation paths to dereference a NULL `arvif->ar` and crash the kernel from adjacent WiFi conditions. ## 6. Manual review recommendation MANUAL CHECK REQUIRED Reason: adjacent-network reachable kernel crash in a wireless driver, but currently supported impact is DoS only and not privilege escalation. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: wifi: ath12k: fix NULL deref in change_sta_links for unready link [ Upstream Commit: cfcea221db933295bf2cd75a7f80d441c7a51e28 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=cfcea221db933295bf2cd75a7f80d441c7a51e28 Changed files: drivers/net/wireless/ath/ath12k/mac.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=cfcea221db933295bf2cd75a7f80d441c7a51e28 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-74366 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74366 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:A/AC:H/PR:N/UI:R/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: 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).