From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-99134][MODERATE 7.0] mac802154: fix data race and NULL deref on local->assoc_dev Date: Wed, 28 Oct 2026 23:41:56 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-99134 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: 5 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: 3cdd8b1abddebbae2582e90294c77b61d5f5aee7 List-Id: CVE: CVE-2026-99134 Priority: MODERATE 7.0 AL-KERNEL base severity: MODERATE KPANIC flag: YES Patch: mac802154: fix data race and NULL deref on local->assoc_dev Commit: 3cdd8b1abddebbae2582e90294c77b61d5f5aee7 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3cdd8b1abddebbae2582e90294c77b61d5f5aee7 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99134 Analysis date: Wed, 28 Oct 2026 23:41:56 -0400 ActionableScore: 5 ActionableScore lower bound: unknown Actionable bucket: Actionable Moderate / Strong Important candidate requiring manual review Manual review required: YES Summary: A nearby malicious IEEE 802.15.4 peer can race association cleanup to trigger a coordinator UAF/NULL dereference or replace active association results before kernel consumption. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-99134 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99134 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-2026-99134 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-99134 CHECK WITH IMPACT FROM ORIG NN LOW | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=5 LEGACY=MODERATE_KPANIC RESULT=SAME (final reconciliation agrees; DECISION: both MODERATE_KPANIC) 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:L/A:H';CWE-362;*CWE-416;**CWE-476;CWE-367;Other CVSS 'AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.9';DESCR 'A race between the mac802154 association path and the association response worker can clear or free local assoc_dev after the worker checks the associating state but before it dereferences the coordinator pointer. This provides a concrete NULL dereference or UAF read primitive and may crash the kernel. A second malicious association response can also replace assoc_status and assoc_addr between separate reads and produce an incoherent association result. For the CVSS the PR:N value is appropriate because a nearby radio peer does not need an authenticated local account or victim privileges. AV:A and AC:H reflect the need for IEEE 802.15.4 radio proximity, an active association attempt, and successful race timing. No UAF write or information disclosure path is established by the affected accesses. Automated impact decision path. The original SimpleNet classifier selected LOW. The primary LLM estimated paranoid CVSS 5.9 and the production ActionableScore returned 5 with recommendation Actionable Moderate / Strong Important candidate requiring manual review. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were CVSS and initial triage stage LOW to MODERATE_KPANIC because the ActionableScore threshold rule was applied. The legacy KP specialist produced a review artifact and its decision was processed by the applicable KP rules. The legacy FD or DH downgrade specialist has no review artifact for this run. Exact triggered rule markers were INCREASED_TO_MODERATE7_FROM_LOW_BASED_ON_GUESSCVSS_AND_ACTIONABLESCOREHIGHER4. The independent weaker Aegis shadow evaluated CVSS 5.9 and ActionableScore 5 with primitive class CLASS_B and manual review REQUIRED. Its independently reconciled impact was MODERATE_KPANIC. The shadow agreed with the final production impact and aggregation did not change that impact. The final reported impact is MODERATE_KPANIC.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate / Strong Important candidate requiring manual review (with actual score 5) MAYBE OOB LOCK NULLPTR INIT RACE LEAK ERRORPATH HARDWARE TEST KPANIC INCREASED_TO_MODERATE7_FROM_LOW_BASED_ON_GUESSCVSS_AND_ACTIONABLESCOREHIGHER4 - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=5 PrimitiveClass=CLASS_B RealUAF=YES HostAdminRequired=NO NamespaceScopedPrivilege=NO ImportantCandidate=YES ManualReview=REQUIRED AutoDowngradeAllowed=NO RequiresHostUID0=NO AuthorizationDecisionBypass=NO ProtectedResourceImpact=NONE B4PendingReview=NO B4PendingConfirmed=NO 1. ActionableScore * Raw base score: 5. * Conservative score: 5; no floor or cap applied. * Raw paranoid score: 5. * Paranoid score: 5; no additional exploit primitive is sufficiently supported. * Final recommended bucket: **Actionable Moderate / Strong Important candidate requiring manual review**:: 2. Signal breakdown * +2 — Real UAF: timeout/error cleanup may free `coord` while the response worker dereferences the stale `local->assoc_dev`. * +2 — Adjacent network reachability: an unauthenticated nearby IEEE 802.15.4 peer can supply the racing association response during a legitimate association attempt. * +1 — Reliable crash concern: the race specifically permits either a NULL dereference or stale-object dereference. * +1 — Integrity impact: a second malicious response can overwrite `assoc_status` and `assoc_addr`, producing an incoherent result later consumed by the association caller. * -1 — Hard timing: successful triggering requires the response/cleanup or repeated-response race described by the patch and hints. * No controlled reclaim, attacker-shaped replacement object, arbitrary write, disclosure, callback control, or LPE is shown. * No extra availability point: it would duplicate the same NULL/UAF crash. * The stale object is structured, but structured-reuse leverage is not awarded because the stale worker only consumes the coordinator’s extended-address field. 3. Reachability analysis The supported attacker is a nearby radio peer, not a local user, namespace administrator, or host administrator. No host UID 0, capability, namespace, or special local account is needed by that peer, although the victim must have initiated an association and the attacker must win a race. The complete path is therefore below host-admin but not namespace-capability scoped. No separate privileged setup beyond an active IEEE 802.15.4 association attempt is established. 4. Primitive and severity reading The patch establishes an active-object UAF read: cleanup can end the coordinator object’s lifetime while the response worker retains and dereferences its pointer. It also establishes attacker-influenced writes to active association result fields, followed by consumption by the privileged local networking path. The specific trust boundary is the nearby radio peer to the local kernel association state. This remains CLASS_B: the shown effects are crash and low-level association-state integrity corruption, not controlled heap reuse or a directed kernel write. ImportantCandidate is retained because the UAF and cross-boundary corrupted-state consumption require exploit and downstream-policy review; this does not prove Important severity, host compromise, or panic reliability. Auto-downgrade is unsafe until the consequences of accepting the incoherent address/status result are resolved. 5. One-sentence report phrase A nearby malicious IEEE 802.15.4 peer can race association cleanup to trigger a coordinator UAF/NULL dereference or replace active association results before kernel consumption. 6. Manual review advice MANUAL CHECK REQUIRED Review downstream use of the accepted short address and status, race reproducibility, and whether corrupted association identity can affect protected networking state beyond the shown crash and low-integrity result. 7. Call-site confidence Call-site confidence: high ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: mac802154: fix data race and NULL deref on local->assoc_dev Commit: 3cdd8b1abddebbae2582e90294c77b61d5f5aee7 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3cdd8b1abddebbae2582e90294c77b61d5f5aee7 Commit description: local->assoc_dev is shared between the association path and the association-response worker without common synchronization. mac802154_perform_association() stores the coordinator pointer and waits for a response. Its timeout and error paths clear the pointer and return to mac802154_associate(), which may then free the coordinator object. Meanwhile, mac802154_rx_mac_cmd_worker() may observe the associating bit and enter mac802154_process_association_resp(), which dereferences assoc_dev. The worker's bit test and the handler's pointer dereference are not atomic with respect to cleanup. Cleanup can clear assoc_dev between them, causing a NULL dereference, or free the coordinator while the response handler still uses the pointer. The recorded result is exposed to the same window. assoc_status and assoc_addr are written by the handler but read by the association path while the associating bit is still set, so a second response for the same request - a malicious one, for instance - can replace them between those reads and leave the caller with an incoherent status and address pair. The response handler only needs the coordinator extended address. Replace assoc_dev with a cached address, removing the pointer lifetime dependency. Protect the cached address and the associating bit with a dedicated spinlock. A READ_ONCE()/WRITE_ONCE() pair would not guarantee an atomic __le64 access on all 32-bit architectures. wpan_dev->association_lock cannot be reused here: nl802154_associate() holds it across rdev_associate(), hence for the whole of mac802154_perform_association() including the wait for the response. A response handler taking that lock would only get it once the association has already given up. Reset the completion, publish the cached address, and set the associating bit while holding the lock. The response handler takes the lock, rechecks the bit and the cached address, records the response, clears the bit, and only then completes the waiter. Thus cleanup cannot pass the handler between its state check and completion, and the cached 64-bit value cannot tear. The handler clears the bit before completing, not the woken waiter: otherwise complete() is issued under the lock and a second (e.g. malicious) response can reacquire it before the waiter and replace the result. So a wait that returns success implies the bit is already clear, and the success and negative-response paths return directly. The transmit-error and timeout paths still clear it under assoc_lock, which serializes any racing response against the cleanup while the call returns the error it already selected. Both paths snapshot assoc_status and assoc_addr under the same lock. Both users run in process context, so a plain spinlock is sufficient. The lock is not held while waiting for the completion. Suggested-by: Miquel Raynal Suggested-by: Xuanqiang Luo Fixes: fefd198 ("mac802154: Handle associating") Cc: stable@vger.kernel.org Signed-off-by: Kaiwen Shi Reviewed-by: Xuanqiang Luo Reviewed-by: Miquel Raynal Link: https://patch.msgid.link/20260829230551.1787432-1-skwkevin@mail.ustc.edu.cn Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman Changed files: net/mac802154/ieee802154_i.h net/mac802154/main.c net/mac802154/scan.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=3cdd8b1abddebbae2582e90294c77b61d5f5aee7 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-99134 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99134 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: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:L/A:H The Best / paranoid CVSS score: 5.9 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: unknown Paranoid ActionableScore: 5 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).