From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-90126][LOW] rtc: pcf8563: fix clock provider leak on unbind [ Upstream Date: Thu, 17 Sep 2026 15:15:55 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-90126 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: 2b5622cf4ee218b6f98d31dbf3fbd44b9b6bd675 List-Id: CVE: CVE-2026-90126 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: rtc: pcf8563: fix clock provider leak on unbind [ Upstream Commit: 2b5622cf4ee218b6f98d31dbf3fbd44b9b6bd675 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2b5622cf4ee218b6f98d31dbf3fbd44b9b6bd675 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90126 Analysis date: Thu, 17 Sep 2026 15:15:55 -0400 ActionableScore: 0 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate Manual review required: NO Summary: No one-sentence report phrase was found. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-90126 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90126 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-2026-90126 LOW https://www.kernelcve.org/list/?q=CVE-2026-90126 CHECK WITH IMPACT FROM ORIG NN LOW Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H';*CWE-401;*CWE-772;**CWE-400;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.4';DESCR 'The pcf8563 RTC driver registered the CLKOUT OF clock provider with of_clk_add_provider but did not remove that provider when the device was unbound or the module was reloaded. Repeated bind/unbind cycles can leak provider structures, OF node references, and global provider list entries, causing gradual resource growth and possible denial of service only after sustained abuse. For the CVSS the PR:H is used because reliable triggering normally requires local administrative control over driver binding or module reload operations. The issue is not network reachable and does not provide a direct memory corruption primitive. Impact is limited to availability, with no supported confidentiality or integrity impact from the patch context.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 0) YES SIMPLEFIX LEAK HARDWARE LINUS NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=0 PrimitiveClass=NONE RealUAF=NO HostAdminRequired=YES NamespaceScopedPrivilege=NO ImportantCandidate=NO ManualReview=NO AutoDowngradeAllowed=YES 1. ActionableScore * Raw conservative score: -1 * Conservative score: 0 * Raw paranoid score: 0 * Paranoid score: 0 * Applied conservative floor/cap: lower bounded -1 -> 0 * Final recommended bucket: **Ordinary Moderate**:: 2. Signal breakdown * +1 Concrete persistent kernel resource/reference leak. `of_clk_add_provider()` allocates and registers an `of_clk_provider`, takes an OF node reference, and adds it to the global provider list, but the unbind path did not remove it. * +1 Paranoid only sustained resource exhaustion possibility. Repeated bind/unbind or module reload cycles can accumulate leaked provider objects and OF node references. * -2 Host-admin-equivalent requirement. Reliable triggering requires local administrative control over driver unbind/bind or module reload on the host. * 0 No real UAF. The patch fixes a missing provider unregister/lifetime cleanup, not stale use after free. * 0 No memory corruption primitive. No OOB, double free, stale dereference, arbitrary write, or controlled reclaim is established. * 0 No C/I impact. The defect supports resource leakage only. * 0 No remote reachability. There is no network-triggered path. * 0 Extra availability not awarded conservatively. The demonstrated effect is gradual leakage, not immediate host-wide failure. 3. Reachability analysis The realistic trigger is local administrative manipulation of the RTC driver lifecycle, such as device unbind/bind or module unload/reload. That is host-admin-equivalent in normal deployments. No namespace-scoped privilege path is established. There is prior hardware/device presence, but the score does not rely on rare hardware reduction. The issue is not a race and does not depend on timing. Sustained repeated operations are needed for meaningful resource exhaustion. 4. Primitive and severity interpretation The exact primitive is a persistent kernel resource/reference leak: a clock provider registration and OF node reference survive device unbind. This is not active structured UAF, not fixed stale storage, and not a repeated release/refcount mutation. The demonstrated consequence is gradual resource growth. The speculative worst case is availability degradation after sustained privileged abuse. PrimitiveClass is NONE because no corruption, authorization bypass, ownership violation, or stale post-lifetime object use is established. ImportantCandidate is NO because there is no meaningful unresolved exploitation leverage beyond privileged resource leakage. AutoDowngradeAllowed is YES because this is a host-admin-triggered resource leak without memory corruption or boundary bypass. 5. One-sentence report phrase The pcf8563 RTC driver leaked CLKOUT OF clock provider registrations and OF node references across device unbind or module reload, allowing only privileged sustained resource exhaustion rather than memory corruption or privilege escalation. 6. Manual review recommendation NO MANUAL CHECK NEEDED Reason: this is a privileged resource/reference leak with no UAF, no corruption primitive, no network exposure, and no authorization boundary bypass. 7. Call-site confidence Call-site confidence: high ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: rtc: pcf8563: fix clock provider leak on unbind [ Upstream Commit: 2b5622cf4ee218b6f98d31dbf3fbd44b9b6bd675 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2b5622cf4ee218b6f98d31dbf3fbd44b9b6bd675 Changed files: drivers/rtc/rtc-pcf8563.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=2b5622cf4ee218b6f98d31dbf3fbd44b9b6bd675 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-90126 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90126 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:L/PR:H/UI:N/S:U/C:N/I:N/A:L The Best / paranoid CVSS vector: AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS score: 4.4 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).