From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-97505][MODERATE 7.0] PCI/sysfs: Add CAP_SYS_ADMIN check to __resource_resize_store() [ Upstream Date: Thu, 24 Sep 2026 18:25:26 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-97505 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: b722a607f858b9cd036075ea0efad553fb98e982 List-Id: CVE: CVE-2026-97505 Priority: MODERATE 7.0 AL-KERNEL base severity: MODERATE KPANIC flag: YES Patch: PCI/sysfs: Add CAP_SYS_ADMIN check to __resource_resize_store() [ Upstream Commit: b722a607f858b9cd036075ea0efad553fb98e982 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b722a607f858b9cd036075ea0efad553fb98e982 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97505 Analysis date: Thu, 24 Sep 2026 18:25:26 -0400 ActionableScore: 5 ActionableScore lower bound: unknown Actionable bucket: Actionable Moderate Manual review required: YES Summary: No one-sentence report phrase was found. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-97505 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97505 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-2026-97505 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-97505 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:N/I:N/A:H';CWE-862;CWE-284;CWE-269;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.7';DESCR 'An authorization check is missing in the PCI sysfs resourceN_resize write path. A local process with write access to a resourceN_resize attribute can request a BAR resize without CAP_SYS_ADMIN. Changing BAR sizing modifies PCI device configuration and can disrupt an active driver or render a device unavailable. For the CVSS the PR:L value is used for the paranoid score because exploitation requires local execution and delegated write access to the specific sysfs attribute but does not require CAP_SYS_ADMIN. The issue is not network reachable. Impact is primarily denial of service through device or driver disruption. No memory corruption information disclosure or privilege escalation primitive is demonstrated by the patch. Standard sysfs permissions normally limit exposure to administrative users. Manual review should confirm the actual attribute mode ACLs and any delegated device management setup.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate (with actual score 5) YES SIMPLEFIX HARDWARE KPANIC INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=5 PrimitiveClass=CLASS_A RealUAF=NO HostAdminRequired=NO NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=YES ManualReview=REQUIRED AutoDowngradeAllowed=NO 1. ActionableScore * Raw conservative score: 5 * Conservative score: 5 * Raw paranoid score: 5 * Paranoid score: 5 * Final recommended bucket: **Actionable Moderate**:: 2. Signal breakdown * +2 Concrete authorization decision bypass. The sysfs store path accepted BAR resize requests without the intended CAP_SYS_ADMIN authorization gate. The patch explicitly restores a mandatory capability check. * +1 Local below-host-admin trigger. The commit explicitly states that the new check prevents unprivileged users from performing BAR resize operations. The attacker must still possess write access to the particular resourceN_resize sysfs attribute. * +1 Integrity plausible. A successful write changes PCI BAR configuration, which is protected device configuration state. * +1 Availability impact realistic. The commit states that resizing a BAR can disrupt active drivers. This can make the affected PCI device or its dependent service unavailable. * No memory-corruption, UAF, OOB, controlled reclaim, arbitrary write, information disclosure, or privilege-escalation signal is established. * No remote-reachability signal. The vulnerable interface is a local sysfs write path. * No extra Availability point for a kernel crash. The supplied evidence supports device or driver disruption, not a demonstrated host kernel crash. * No privilege penalty. The patch expressly identifies unprivileged operation as the authorization problem. Requiring write access to the sysfs file is a reachability condition, not proof of host-admin-equivalent privilege. 3. Reachability analysis The attacker is a local process that can write to a PCI resourceN_resize sysfs attribute. Before the fix, such a process could resize a BAR without CAP_SYS_ADMIN. The supplied evidence positively supports below-host-admin reachability because the commit explicitly describes preventing unprivileged users from performing this operation. However, practical reachability depends on the ownership, mode bits, ACLs, device-management service policy, and sysfs exposure for the particular resourceN_resize attribute. The added capable(CAP_SYS_ADMIN) check is evaluated through the current task capability context. The supplied patch does not establish that the complete operation, including access to the relevant host PCI sysfs device, can be performed solely with an attacker-created user namespace or network namespace. Therefore NamespaceScopedPrivilege is UNKNOWN. No network trigger, special hardware attack, race, firmware compromise, or prior host-side topology manipulation is established by the patch. A PCI device must naturally exist, but this is not evidence of a rare-hardware-only attack condition. 4. Primitive and severity interpretation The exact primitive is a concrete local authorization bypass. The missing CAP_SYS_ADMIN check changes the security decision from requiring administrative capability to allowing a BAR resize based only on filesystem write permission. This is CLASS_A because the patch directly restores a missing mandatory authorization gate for a security-relevant device-management operation. It is not a memory-lifetime issue. There is no UAF, stale object, repeated release, refcount mutation, active-object corruption, or controlled memory reuse. The demonstrated consequence is unauthorized PCI BAR reconfiguration with potential active-driver disruption or device unavailability. A stronger consequence such as host compromise, DMA-based memory corruption, confidentiality impact, or privilege escalation is speculative and is not scored. ImportantCandidate is YES because a meaningful authorization boundary is concretely bypassed. AutoDowngradeAllowed is NO because automatically treating the issue as ordinary device-local behavior could discard a real missing-capability security boundary. Manual review is required to determine whether affected deployments delegate write access to resourceN_resize, expose the relevant devices to service accounts or containers, and depend on the affected PCI devices for storage, networking, or other critical services. Likely operational severity is Actionable Moderate. The primitive is security-relevant, but the supplied evidence does not establish a direct path to kernel memory corruption, host-wide denial of service, sensitive-data access, or local privilege escalation. 5. One-sentence report phrase A missing CAP_SYS_ADMIN check in the PCI resourceN_resize sysfs write path allowed a local user with write access to resize a PCI BAR and potentially disrupt the active device driver or device availability. 6. Manual review recommendation MANUAL CHECK REQUIRED Verify the effective permissions and ACLs of resourceN_resize attributes, delegated PCI device-management paths, container exposure, and the operational criticality of affected PCI devices. 7. Call-site confidence Call-site confidence: medium ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: PCI/sysfs: Add CAP_SYS_ADMIN check to __resource_resize_store() [ Upstream Commit: b722a607f858b9cd036075ea0efad553fb98e982 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b722a607f858b9cd036075ea0efad553fb98e982 Changed files: drivers/pci/pci-sysfs.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=b722a607f858b9cd036075ea0efad553fb98e982 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-97505 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97505 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:N/I:N/A:L The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS score: 4.7 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: 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).