From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-97552][LOW] xfs: initialise error in xfs_defer_finish_one() Date: Fri, 25 Sep 2026 08:14:04 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-97552 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: 2 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: 30748a24b9f04f9a83599ba907cc8fbff0729f3c List-Id: CVE: CVE-2026-97552 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: xfs: initialise error in xfs_defer_finish_one() Commit: 30748a24b9f04f9a83599ba907cc8fbff0729f3c Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=30748a24b9f04f9a83599ba907cc8fbff0729f3c Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97552 Analysis date: Fri, 25 Sep 2026 08:14:04 -0400 ActionableScore: 2 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-2026-97552 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97552 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-2026-97552 LOW https://www.kernelcve.org/list/?q=CVE-2026-97552 CHECK WITH IMPACT FROM ORIG NN MODERATE 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-457;CWE-908;CWE-703;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 uninitialized error value in xfs_defer_finish_one can be returned when a deferred pending item has no work entries. During XFS online repair this can be interpreted as a fatal error and force SHUTDOWN_CORRUPT_INCORE, making the affected XFS filesystem unavailable. For the CVSS the PR:L paranoid score assumes a delegated repair service account or reduced capability administrator can reliably invoke the online repair path. The issue is not network reachable and requires CONFIG_XFS_ONLINE_REPAIR. Impact is denial of service for the affected filesystem. The patch context does not show a memory corruption primitive, information disclosure, integrity modification, or privilege escalation path.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2) YES DISK SIMPLEFIX LINUS DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_GUESSCVSS_AND_CIANNH YES NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=2 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=UNKNOWN NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=NO ManualReview=NO AutoDowngradeAllowed=YES 1. ActionableScore * Raw conservative score: 2 * Conservative score: 2 * Raw paranoid score: 2 * Paranoid score: 2 * Final recommended bucket: **Ordinary Moderate**:: 2. Signal breakdown * +1 Reliable filesystem denial of service. A nonzero uninitialized stack value can be treated as a fatal deferred-operation error and trigger SHUTDOWN_CORRUPT_INCORE. * +1 Important filesystem path. The affected code is in XFS deferred-operation processing used by XFS online repair, and the resulting shutdown can make the affected filesystem unavailable. * +0 No memory corruption primitive. The patch initializes a returned integer value and does not establish UAF, double free, invalid pointer use, out-of-bounds access, stale object access, or refcount mutation. * +0 No confidentiality or integrity impact. The uninitialized value changes error handling only. No disclosure path, unauthorized metadata modification, or cross-owner filesystem write is established. * +0 No local unprivileged trigger bonus. The supplied context does not establish that an ordinary unprivileged user can initiate the complete XFS online repair path. * +0 No host-admin penalty. The supplied patch does not positively establish the complete privilege requirement for invoking online repair. * +0 No special hardware, remote network, race, controlled reclaim, or attacker-controlled payload is established. * +0 No additional availability point. The filesystem shutdown is the same demonstrated DoS consequence already counted above. 3. Reachability analysis The vulnerable path requires an XFS filesystem and CONFIG_XFS_ONLINE_REPAIR. The immediate trigger is an item-less deferred barrier created during xfs_reap_ag_blocks, followed by xfs_defer_finish_one returning an indeterminate error value. The supplied patch does not show the userspace entry point, capability checks, or exact operational permissions for the complete online repair sequence. Therefore HostAdminRequired is UNKNOWN rather than YES or NO. There is no evidence that the relevant operation can be completed by an attacker using only namespace-scoped privileges, so NamespaceScopedPrivilege is UNKNOWN. The issue is not network reachable. No special device, firmware, DMA, race condition, attacker-controlled storage payload, or prior attacker-controlled privileged setup is established by the supplied evidence. 4. Primitive and severity interpretation The exact primitive is an uninitialized local integer returned through an error-handling path when dfp_work is empty. A nonzero stack residue can be interpreted as a fatal XFS deferred-operation failure and can force SHUTDOWN_CORRUPT_INCORE during online repair. This is not a UAF, stale-object access, ownership violation, COW violation, repeated release, refcount mutation, or active memory-corruption primitive. It is an invalid-state and error-propagation bug with a demonstrated filesystem availability consequence. PrimitiveClass is CLASS_C because the established behavior is filesystem shutdown and DoS without an independently useful corruption or security-boundary primitive. ImportantCandidate is NO because no meaningful exploitation leverage beyond the filesystem shutdown is supported. AutoDowngradeAllowed is YES because the patch-supported impact is constrained to an erroneous shutdown of the affected XFS filesystem and no unresolved corruption primitive remains. Likely operational severity is low to ordinary Moderate depending on whether the affected XFS filesystem is critical production storage. The provided paranoid CVSS availability interpretation can be useful for asset-priority decisions, but it does not establish privilege escalation, confidentiality loss, integrity loss, or an Important-class kernel primitive. 5. One-sentence report phrase An uninitialized error return in XFS deferred-operation processing can incorrectly force SHUTDOWN_CORRUPT_INCORE during online repair, causing denial of service for the affected XFS filesystem. 6. Manual review recommendation NO MANUAL CHECK NEEDED The patch establishes a deterministic error-handling defect and filesystem shutdown outcome, but no memory corruption, ownership violation, security-boundary bypass, or privilege-escalation primitive. 7. Call-site confidence Call-site confidence: medium ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: xfs: initialise error in xfs_defer_finish_one() Commit: 30748a24b9f04f9a83599ba907cc8fbff0729f3c Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=30748a24b9f04f9a83599ba907cc8fbff0729f3c Commit description: xfs_defer_finish_one() declares error without an initialiser and only assigns it inside the loop over dfp->dfp_work. When that list is empty the loop body never runs, control falls through to the "Done with the dfp, free it" path, and the function returns an indeterminate value. An item-less pending item reaches this through xfs_defer_add_barrier(), which xfs_reap_ag_blocks() uses on any CONFIG_XFS_ONLINE_REPAIR kernel. xfs_defer_finish_noroll() treats any non-EAGAIN return as fatal, so a non-zero stack value turns a successful barrier into a SHUTDOWN_CORRUPT_INCORE in the middle of a repair. Zero is the correct result: reaching the free path means the item loop drained without a non-zero error. Fixes: 3f3cec0 ("xfs: force small EFIs for reaping btree extents") Cc: stable@vger.kernel.org Signed-off-by: Javier Tia Reviewed-by: Darrick J. Wong Signed-off-by: Carlos Maiolino Signed-off-by: Greg Kroah-Hartman Changed files: fs/xfs/libxfs/xfs_defer.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=30748a24b9f04f9a83599ba907cc8fbff0729f3c ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-97552 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97552 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: 2 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).