From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-99019][LOW] scsi: ch: Do not keep references to data transfer element devices [ Upstream Date: Mon, 26 Oct 2026 20:34:47 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-99019 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: ec6ecab1b7577ae555ee6b81480814d123dd9ec0 List-Id: CVE: CVE-2026-99019 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: scsi: ch: Do not keep references to data transfer element devices [ Upstream Commit: ec6ecab1b7577ae555ee6b81480814d123dd9ec0 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ec6ecab1b7577ae555ee6b81480814d123dd9ec0 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99019 Analysis date: Mon, 26 Oct 2026 20:34:47 -0400 ActionableScore: 2 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate Manual review required: NO Summary: A missing `scsi_device_put()` persistently pins changer-reported SCSI devices, blocking address reuse and driver unload until reboot without memory corruption or authorization impact. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-99019 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99019 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-2026-99019 LOW https://www.kernelcve.org/list/?q=CVE-2026-99019 CHECK WITH IMPACT FROM ORIG NN LOW | AEGIS IMPACT LOW AEGIS_AS=1 LEGACY=LOW RESULT=SAME (final reconciliation agrees; DECISION: both LOW) Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L';*CWE-772;CWE-911;*CWE-401;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '3.3';DESCR 'The SCSI changer driver retains a reference returned by scsi_device_lookup for every reported data transfer element and never releases it. Removing a drive can therefore leave its scsi_device permanently present on the host device list, preventing reuse of the same SCSI address and blocking low level driver module unload until reboot. For the CVSS the PR:H base value reflects that reliable triggering normally requires administrative control over SCSI changer discovery and device removal. For the CVSS the PR:L paranoid value covers deployments where a less privileged service account can create and remove virtual tape libraries. The demonstrated primitive is resource retention rather than UAF or memory corruption, and no confidentiality or integrity impact is supported. Automated impact decision path. The original SimpleNet classifier selected LOW. The primary LLM estimated paranoid CVSS 3.3 and the production ActionableScore returned 2 with recommendation Ordinary Moderate. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. No severity changing production threshold or specialist override was recorded. The legacy KP specialist has no review artifact for this run. The legacy FD or DH downgrade specialist has no review artifact for this run. The independent weaker Aegis shadow evaluated CVSS 2.2 and ActionableScore 1 with primitive class CLASS_C and manual review REQUIRED. Its independently reconciled impact was LOW. The shadow agreed with the final production impact and aggregation did not change that impact. The final reported impact is LOW.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2) MAYBE NOMEMCHK LEAK HARDWARE LINUS BOOT - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=2 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=UNKNOWN NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=NO ManualReview=NO AutoDowngradeAllowed=YES RequiresHostUID0=UNKNOWN AuthorizationDecisionBypass=NO ProtectedResourceImpact=NONE B4PendingReview=NO B4PendingConfirmed=NO 1. ActionableScore * Raw base score: 2. * Conservative score: 2; no floor or cap applied. * Raw paranoid score: 2. * Paranoid score: 2; lower-privilege virtual-library control is possible but not sufficiently established for an additional reachability point. * Final recommended bucket: **Ordinary Moderate**:: 2. Signal breakdown * +1 Concrete persistent kernel reference leak: each successful `scsi_device_lookup()` takes a reference that the old `dt[]` storage retains without any corresponding `scsi_device_put()`. * +1 Availability impact: retained references prevent reuse of the affected SCSI address and block low-level driver module unload until reboot. * No UAF, OOB access, overwrite, repeated release, authorization bypass, disclosure, or protected-state corruption is shown. * No additional resource-exhaustion point: accumulation exists, but host-wide memory exhaustion is not demonstrated. * No privilege or hardware penalty: administrative control is plausible, but the complete trigger privilege and any physical-hardware requirement are not positively established. 3. Reachability analysis The demonstrated sequence requires changer discovery followed by removal of reported drives or repeated virtual-library creation/removal. The mhvtl example establishes repeatability, but does not establish that an ordinary user can perform the complete operation. A delegated service account is plausible but unproven. There is no namespace capability analysis, remote path, race, or timing requirement. 4. Primitive and severity reading The primitive is a persistent `scsi_device` reference leak, not stale post-lifetime use: the leaked reference deliberately prevents object destruction. Its proven effects are device-address retention and inability to unload the associated driver until reboot. It is CLASS_C operational invalid-state/resource retention, with no useful corruption or security-boundary primitive. Therefore it is not an Important candidate and can be automatically downgraded. 5. One-sentence report phrase A missing `scsi_device_put()` persistently pins changer-reported SCSI devices, blocking address reuse and driver unload until reboot without memory corruption or authorization impact. 6. Manual review advice NO MANUAL CHECK NEEDED The patch and commit establish a bounded resource-lifetime leak with low availability impact and no unresolved exploit primitive. 7. Call-site confidence Call-site confidence: high ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: scsi: ch: Do not keep references to data transfer element devices [ Upstream Commit: ec6ecab1b7577ae555ee6b81480814d123dd9ec0 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ec6ecab1b7577ae555ee6b81480814d123dd9ec0 Changed files: drivers/scsi/ch.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=ec6ecab1b7577ae555ee6b81480814d123dd9ec0 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-99019 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99019 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:L/UI:N/S:U/C:N/I:N/A:L The Best / paranoid CVSS score: 3.3 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).