From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-64222][MODERATE 7.0] octeontx2-pf: avoid double free of pool->stack on AQ init failure [ Upstream Date: Fri, 24 Jul 2026 12:24:14 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-64222 X-AL-KERNEL-Priority: MODERATE 7.0 X-AL-KERNEL-Severity: MODERATE 7.0 X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 5 X-AL-KERNEL-ActionableScore-Lower: 3 X-AL-KERNEL-Commit: e6e9bc0bf963662b7042048ab0281014625d4cb4 List-Id: CVE: CVE-2026-64222 Priority: MODERATE 7.0 AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: octeontx2-pf: avoid double free of pool->stack on AQ init failure [ Upstream Commit: e6e9bc0bf963662b7042048ab0281014625d4cb4 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e6e9bc0bf963662b7042048ab0281014625d4cb4 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64222 Analysis date: Fri, 24 Jul 2026 12:24:14 -0400 ActionableScore: 5 ActionableScore lower bound: 3 Actionable bucket: Actionable Moderate at minimum Manual review required: YES Summary: A double free in the OcteonTX2/CN20K NIC AQ initialization error path can leave pool stack stale after qmem_free and later free it again during shared cleanup, causing local kernel memory corruption and likely DoS on affected hardware. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-64222 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64222 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-2026-64222 MODERATE CHECK WITH IMPACT FROM ORIG NN LOW 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-415;*CWE-416;*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 double free can occur in the OcteonTX2/CN20K NIC driver when AQ pool initialization fails after pool stack has already been freed locally. The stale pool stack pointer can later be passed to the shared cleanup path and freed again during partial initialization unwind. This is a local driver management path and is not directly network reachable. For the CVSS the PR:L in the paranoid score is used only for environments where a non-admin local service account, container root, or delegated net admin context can trigger device reset or driver reinitialization. In normal deployments PR:H is more realistic because the path is tied to privileged NIC and driver management. Impact is at least local denial of service via kernel crash and in worst case may allow confidentiality or integrity impact because double free is a memory corruption primitive.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 4) YES REMOTE INIT ERRORPATH NETWORK HARDWARE LINUS DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 YES NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=5 ActionableScoreLower=3 ## 1. ActionableScore * Conservative score: 3 * Paranoid score: 5 * Final recommended bucket: **Actionable Moderate at minimum**:: ## 2. Signal breakdown Conservative signals: * Generic memory corruption: +2. The patch fixes a confirmed double free of pool->stack. * Real lifetime corruption: +1. The pointer remains stale after qmem_free and is later consumed by a shared cleanup path. * Reliable kernel crash / strong DoS: +1. A double free in kernel driver cleanup can realistically crash the kernel or corrupt allocator state. * Privileged kernel/device-management memory corruption path: +1. The bug is in NIC queue/pool initialization and cleanup, close to firmware mailbox and device-management logic. * Requires admin/root/CAP_* in typical deployments: -2. Triggering driver load, reset, queue initialization, or recovery normally requires host administrative control. * Rare hardware/device-specific condition: -1. The affected path requires OcteonTX2/CN20K hardware and a specific AQ initialization failure path. Paranoid additional interpretation: * Firmware-mediated external influence: +1. One failure path depends on otx2_sync_mbox_msg and device/firmware mailbox behavior. * Weak LPE concern: +1. Double free is a real memory corruption primitive, but no controlled reclaim, overwrite target, callback control, or exploit chain is shown. * Confidentiality impact plausible: +1. In the worst defensible case, allocator corruption from double free could affect kernel object lifetime. * Integrity impact plausible: +1. Same reason, but this remains speculative without a demonstrated reuse primitive. * Reduced privilege / delegated device-control interpretation: -1. In some deployments a service account, container root, or delegated net admin context may trigger reset or reinitialization without full host-root equivalence. ## 3. Reachability analysis The bug is local and not directly network reachable through packet processing. A realistic trigger requires the OcteonTX2/CN20K NIC driver, affected hardware, and an AQ initialization failure such as mailbox sync failure or allocation failure. In normal deployments, the required operations are tied to privileged driver/device management, so PR:H is more realistic for CVSS-style reasoning. A paranoid interpretation can use PR:L only if a reduced-privilege service, container root with delegated device access, or local operator can provoke driver reset or reinitialization. Runtime reproduction is hardware-dependent, and the commit explicitly notes that validation was not performed because the path requires OcteonTX2/CN20K hardware. Call-site confidence: medium-high. The commit explicitly identifies the later cleanup path through otx2_sq_aura_pool_init and otx2_aura_pool_free, but the full caller code is not included in the pasted diff. ## 4. Severity interpretation This is more than an ordinary Moderate correctness issue because it is a confirmed double free, not just a leak or validation-only fix. Realistic exploitation is likely limited to local privileged DoS on specific hardware, because there is no evidence of attacker-controlled reclaim, object replacement, arbitrary write, or network trigger. The paranoid score treats it as Actionable Moderate because double free is a kernel memory-corruption primitive and should not be auto-closed without manual review, even though practical LPE evidence is weak. ## 5. One-sentence report phrase A double free in the OcteonTX2/CN20K NIC AQ initialization error path can leave pool stack stale after qmem_free and later free it again during shared cleanup, causing local kernel memory corruption and likely DoS on affected hardware. ## 6. Manual review recommendation MANUAL CHECK REQUIRED Reason: confirmed double free and stale pointer lifetime bug in kernel driver cleanup. Practical exploitability is hardware-specific and likely privileged, but memory corruption makes auto-close inappropriate. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: octeontx2-pf: avoid double free of pool->stack on AQ init failure [ Upstream Commit: e6e9bc0bf963662b7042048ab0281014625d4cb4 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e6e9bc0bf963662b7042048ab0281014625d4cb4 Changed files: drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.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=e6e9bc0bf963662b7042048ab0281014625d4cb4 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-64222 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64222 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: 3 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: NO 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).