From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-72026][LOW] irqchip/irq-riscv-imsic-early: Fix fwnode leak on state setup failure commit 1358126fbed104e5657955d3ba029b283687ba02 upstream. Date: Sat, 15 Aug 2026 21:30:31 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-72026 X-AL-KERNEL-Priority: LOW X-AL-KERNEL-Severity: LOW X-AL-KERNEL-Base-Severity: LOW X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 0 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: a27f17bad38c5fea3c73281517869af0089a0451 List-Id: CVE: CVE-2026-72026 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: irqchip/irq-riscv-imsic-early: Fix fwnode leak on state setup failure commit 1358126fbed104e5657955d3ba029b283687ba02 upstream. Commit: a27f17bad38c5fea3c73281517869af0089a0451 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a27f17bad38c5fea3c73281517869af0089a0451 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72026 Analysis date: Sat, 15 Aug 2026 21:30:31 -0400 ActionableScore: 0 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate / Low-like Manual review required: NO Summary: A boot-time RISC-V IMSIC ACPI initialization error path can leak a firmware node reference if state setup fails, but exploitation requires privileged firmware or platform control and the practical impact is limited to a small resource leak. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72026 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72026 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: LOW Manual review required: NO A detailed explanation of the methodology and priority rules is included at the end of this message. ====================================================================== AL-KERNEL CLASSIFICATION RESULT ====================================================================== CVE-2026-72026 LOW 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:H/UI:N/S:U/C:N/I:N/A:L';*CWE-401;*CWE-772;CWE-459;BEST CVSS score: '1.9';DESCR 'A firmware node reference leak can occur in the RISC V IMSIC early ACPI initialization path when imsic_setup_state fails after imsic_acpi_fwnode has already been allocated. The function returned immediately on that error path and left the allocated fwnode referenced through the global pointer. For the CVSS the PR:H is used because reliable triggering normally requires control over boot time ACPI or platform configuration rather than ordinary local user actions. The issue is not network reachable and does not provide a memory corruption primitive. Impact is limited to low availability impact from a small boot time resource leak.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 0) SKIP CVE-2026-72026 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: fbe826b1c10699a70b81a441fe47b817d1019f37 YES NO NO unknown MAYBE INIT SIMPLEFIX LEAK ERRORPATH LINUS - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=0 ## 1. ActionableScore * Conservative score: 0 * Paranoid score: 0 * Final recommended bucket: **Ordinary Moderate / Low-like** ## 2. Signal breakdown Triggered or considered signals: * Firmware-mediated external influence: +1 The failing path depends on ACPI or platform firmware state during early IMSIC initialization. * Requires admin/root/platform control in typical deployments: -2 Reliable triggering generally requires control over boot-time ACPI tables, firmware, platform configuration, or equivalent privileged setup. * Rare AND difficult-to-reach subsystem/configuration: -1 This is RISC-V IMSIC ACPI early irqchip initialization, not a broadly reachable runtime interface. Not awarded: * Remote reachable: +0 No network path exists. * Local unprivileged trigger: +0 Ordinary local users cannot normally trigger early ACPI irqchip initialization failure. * Memory corruption: +0 The patch fixes a leaked fwnode reference, not UAF, OOB, double-free, or type confusion. * Real lifetime corruption: +0 This is a missing put/free on an error path, not stale object reuse or use-after-free. * Reliable kernel crash / strong DoS: +0 The described impact is a small one-shot boot-time resource leak, not a reliable crash. * Availability impact realistic: +0 The leak is too limited to count as practical system-wide resource exhaustion. Score floor applied at 0. ## 3. Reachability analysis The bug is reachable only during early RISC-V IMSIC ACPI initialization. A normal local user cannot repeatedly exercise this path after boot. Namespaces and containers do not lower the privilege requirement because the affected code runs before ordinary user workloads and container contexts exist. The realistic attacker model would require control over firmware, ACPI tables, boot configuration, or a faulty platform environment. The path is not network reachable and is not a default runtime attack surface. Call-site confidence: high, because the patch shows the exact allocation failure path and cleanup path inside `imsic_early_acpi_init()`. ## 4. Severity interpretation This behaves like a Low-like resource leak rather than an actionable Moderate or Important kernel vulnerability. Theoretical impact is limited to a leaked firmware node reference and stale global pointer on an initialization error path. There is no evidence of memory corruption, privilege escalation, sensitive data exposure, persistent resource exhaustion, or a runtime trigger that an unprivileged user can control. ## 5. One-sentence report phrase A boot-time RISC-V IMSIC ACPI initialization error path can leak a firmware node reference if state setup fails, but exploitation requires privileged firmware or platform control and the practical impact is limited to a small resource leak. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED This can be auto-closed for practical triage because it is a low-impact boot-time cleanup bug with no network reachability, no unprivileged trigger, no memory corruption primitive, and no plausible privilege escalation path. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: irqchip/irq-riscv-imsic-early: Fix fwnode leak on state setup failure commit 1358126fbed104e5657955d3ba029b283687ba02 upstream. Commit: a27f17bad38c5fea3c73281517869af0089a0451 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a27f17bad38c5fea3c73281517869af0089a0451 Commit description: imsic_early_acpi_init() allocates a firmware node before setting up the IMSIC state. If imsic_setup_state() fails, the function returns without freeing the allocated fwnode. Free the fwnode and clear the global pointer on this error path, matching the cleanup already done when imsic_early_probe() fails. [ tglx: Use a common cleanup path instead of copying code around ] Fixes: fbe826b1c106 ("irqchip/riscv-imsic: Add ACPI support") Signed-off-by: Haoxiang Li Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260623073744.2009137-1-haoxiang_li2024@163.com Signed-off-by: Greg Kroah-Hartman Diffstat -rw-r--r-- drivers/irqchip/irq-riscv-imsic-early.c 15 Changed files: drivers/irqchip/irq-riscv-imsic-early.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=a27f17bad38c5fea3c73281517869af0089a0451 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72026 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72026 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: Not available The Best / paranoid CVSS vector: AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L The Best / paranoid CVSS score: 1.9 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: 0 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: LOW KPANIC detected for this report: NO Published priority for this report (same as in Subject): LOW 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).