From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-99001][IMPORTANT] drm/xe/i2c: cancel the client work on remove [ Upstream Date: Mon, 26 Oct 2026 14:36:16 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-99001 X-AL-KERNEL-Priority: IMPORTANT X-AL-KERNEL-Severity: IMPORTANT X-AL-KERNEL-Base-Severity: IMPORTANT X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 4 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: 2efa187fd4c9b8d7edcae0c1acf46739ce39fd01 List-Id: CVE: CVE-2026-99001 Priority: IMPORTANT AL-KERNEL base severity: IMPORTANT KPANIC flag: NO Patch: drm/xe/i2c: cancel the client work on remove [ Upstream Commit: 2efa187fd4c9b8d7edcae0c1acf46739ce39fd01 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2efa187fd4c9b8d7edcae0c1acf46739ce39fd01 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99001 Analysis date: Mon, 26 Oct 2026 14:36:16 -0400 ActionableScore: 4 ActionableScore lower bound: unknown Actionable bucket: Borderline / manual review recommended Manual review required: YES Summary: Xe I2C removal can race queued client work, causing stale adapter use and a fixed-offset client-pointer write through a freed devm work context. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-99001 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99001 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: IMPORTANT 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-2026-99001 IMPORTANT https://www.kernelcve.org/list/?q=CVE-2026-99001 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT IMPORTANT AEGIS_AS=6 LEGACY=IMPORTANT RESULT=SAME INDEPENDENT_LEGACY=MODERATE_KPANIC INDEPENDENT_RESULT=DIFF TEMP_KPANIC_MERGE=IMPORTANT_WINS_DISAGREEMENT PRE_MERGE_LEGACY=MODERATE_KPANIC (final reconciliation agrees; DECISION: both IMPORTANT) Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H';*CWE-416;CWE-362;*CWE-672;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '7';DESCR 'A race in xe_i2c_remove can leave xe_i2c_client_work queued or running while the I2C adapter and the devm allocated struct xe_i2c are being released. The callback can dereference a freed adapter in i2c_new_client_device and can write the new client pointer through freed xe_i2c memory, providing a concrete UAF access and potential memory corruption primitive rather than a warning only. For the CVSS the PR:H base value reflects that reliable device unbind, driver removal, or equivalent Xe teardown normally requires administrative control. For the CVSS the PR:L paranoid value covers deployments that delegate device lifecycle operations to a container or service account. AC:H reflects the required workqueue and teardown timing window. Impact is at least a local denial of service via kernel crash and in the worst defensible case may allow privilege escalation through kernel memory corruption. Automated impact decision path. The original SimpleNet classifier selected MODERATE_KPANIC. The primary LLM estimated paranoid CVSS 7 and the production ActionableScore returned 4 with recommendation Borderline / manual review recommended. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were final reconciliation stage MODERATE_KPANIC to IMPORTANT because KP specialist did not establish a qualifying panic. 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 TEMP_KPANIC_MERGE_IMPORTANT_WINS and KPANIC_UNSUPPORTED_REMOVED. The independent weaker Aegis shadow evaluated CVSS 0.8 and ActionableScore 6 with primitive class CLASS_B and manual review REQUIRED. Its independently reconciled impact was IMPORTANT. Cross model aggregation changed the production result under an enabled evidence gated merge rule. The final reported impact is IMPORTANT.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended (with actual score 4) MAYBE USB INIT UAF HARDWARE TEMP_KPANIC_MERGE_IMPORTANT_WINS KPANIC_UNSUPPORTED_REMOVED - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=4 PrimitiveClass=CLASS_B RealUAF=YES HostAdminRequired=UNKNOWN NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=NO ManualReview=RECOMMENDED AutoDowngradeAllowed=YES RequiresHostUID0=UNKNOWN AuthorizationDecisionBypass=NO ProtectedResourceImpact=NONE B4PendingReview=NO B4PendingConfirmed=NO 1. ActionableScore * Raw base score: 4. * Conservative score: 4; no floor or cap applied. * Raw paranoid score: 4. * Paranoid score: 4; no separate controlled-reuse or post-free-state primitive supports another point. * Final recommended bucket: **Borderline / manual review recommended**:: 2. Signal breakdown * +2 — Real UAF/lifetime violation: queued work can execute after the adapter is released or after the devm-allocated `struct xe_i2c` is freed. * +1 — Constrained post-free overwrite: the callback can store a newly created client pointer into `i2c->client[]` through freed `xe_i2c` storage. The offset and kernel-derived payload are fixed; target selection is not shown. * +1 — Plausible kernel crash/strong DoS from stale adapter dereference or callback execution through freed context. * No race penalty: a teardown/workqueue ordering is required, but the supplied evidence does not establish a genuinely narrow or uncontrollable timing window. * No structured-stale leverage: attacker-controlled reclaim, replacement contents, callbacks from reclaimed data, or directed target selection are not shown. * No extra availability, confidentiality, integrity, arbitrary-write, or LPE points. * NEW52/B5-R does not apply: there is no retry-accumulated heap OOB write. * No repeated release/refcount mutation is shown; FLOOR 5 does not apply. 3. Reachability analysis The vulnerable sequence requires Xe I2C teardown while notifier-scheduled work remains queued or running. Normal device unbind/removal commonly involves administrative device-lifecycle control, but the supplied patch does not prove the complete trigger is restricted to effective host administration or available through delegated/container privileges. Therefore both host-admin and namespace scope remain unknown. No ordinary render-node ioctl trigger, attacker-controlled retry loop, special sysctl, or externally controllable hot-unplug path is established. 4. Primitive and severity reading This is a real asynchronous teardown UAF involving fixed stale objects: a released DesignWare adapter and a devm-freed `xe_i2c` work context. It is stronger than a warning-only race because a pointer store through freed storage is explicitly described. However, the stale operation is teardown-bound, and neither controlled reclaim nor attacker-shaped post-free state is shown. It therefore remains constrained CLASS_B rather than CLASS_A. The shown impact is kernel memory misuse and plausible crash. Exploitation through reuse of the freed allocation is theoretical. `ImportantCandidate=NO` and `AutoDowngradeAllowed=YES` reflect the fixed, low-control asynchronous context, while manual review remains appropriate because the callback performs a concrete post-free write. 5. One-sentence report phrase Xe I2C removal can race queued client work, causing stale adapter use and a fixed-offset client-pointer write through a freed devm work context. 6. Manual review advice MANUAL CHECK RECOMMENDED Confirm the actual permissions and repeatability of Xe device teardown and whether slab reuse can occur before the stale pointer store. 7. Call-site confidence Call-site confidence: high ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/xe/i2c: cancel the client work on remove [ Upstream Commit: 2efa187fd4c9b8d7edcae0c1acf46739ce39fd01 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2efa187fd4c9b8d7edcae0c1acf46739ce39fd01 Changed files: drivers/gpu/drm/xe/xe_i2c.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=2efa187fd4c9b8d7edcae0c1acf46739ce39fd01 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-99001 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99001 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:H/UI:N/S:U/C:L/I:L/A:H The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H The Best / paranoid CVSS score: 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: unknown 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: IMPORTANT KPANIC detected for this report: NO Published priority for this report (same as in Subject): IMPORTANT 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).