From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-72097][LOW] dm-verity: fix a possible NULL pointer dereference commit e72b793ae440f6900fb17a4b8518c707b5cd3e17 upstream. Date: Sun, 16 Aug 2026 00:26:04 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-72097 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: 0 X-AL-KERNEL-Commit: 7d4f1d307ac0f4f55cebeb192a90a235aa060ed1 List-Id: CVE: CVE-2026-72097 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: dm-verity: fix a possible NULL pointer dereference commit e72b793ae440f6900fb17a4b8518c707b5cd3e17 upstream. Commit: 7d4f1d307ac0f4f55cebeb192a90a235aa060ed1 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7d4f1d307ac0f4f55cebeb192a90a235aa060ed1 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72097 Analysis date: Sun, 16 Aug 2026 00:26:04 -0400 ActionableScore: 2 ActionableScore lower bound: 0 Actionable bucket: Ordinary Moderate / Low-like. Not an Actionable Moderate Manual review required: NO Summary: A missing NULL check in the dm-verity LoadPin helper can let a local privileged or delegated device-mapper actor trigger a kernel NULL-pointer dereference when a DM device has no live table, causing denial of service only. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72097 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72097 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-2026-72097 LOW CHECK WITH IMPACT FROM ORIG NN MODERATE 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:H';**CWE-476;CWE-252;CWE-703;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.5';DESCR 'dm-verity LoadPin helper can dereference a NULL live device mapper table when checking whether a block device is trusted. A local attacker or local process that can cause dm_verity_loadpin_is_bdev_trusted to run on a DM device with no active table may trigger a kernel crash. For the CVSS the PR:L is used for the paranoid score because some deployments may delegate device mapper control to a reduced capability local administrator or service account, while the normal reliable trigger usually requires CAP_SYS_ADMIN. The issue is not network reachable and there is no evidence of a UAF, out of bounds write, information leak, or privilege escalation primitive. Impact is denial of service via NULL-pointer dereference only.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like. Not an Actionable Moderate (with actual score 1) SKIP CVE-2026-72097 UNKNOWN SKIP No affected files built, so skip this CVE NO - - unknown MAYBE NULLPTR DISK SIMPLEFIX HARDWARE LINUS DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=2 ActionableScoreLower=0 ## 1. ActionableScore * Conservative score: 0 * Paranoid score: 2 * Final recommended bucket: **Ordinary Moderate / Low-like. Not an Actionable Moderate**:: ## 2. Signal breakdown Conservative signals: * Reliable kernel crash / strong DoS: +1. The patch fixes a direct NULL pointer dereference of `table->num_targets` when `dm_get_live_table()` returns NULL. * Important filesystem/storage path: +1. The affected code is in dm-verity LoadPin integration, which is storage and trust-policy adjacent. * Requires admin/root/CAP_SYS_ADMIN in typical deployments: -2. Creating or manipulating device-mapper devices and table state normally requires administrative privileges. Paranoid adjustment: * The paranoid score removes the full privilege penalty and treats delegated device-mapper control by a reduced-privilege service or container-like admin as possible. This raises the practical triage score to 2. * No local unprivileged trigger is awarded because ordinary unprivileged users normally cannot create or control table-less DM devices. Not awarded: * No remote/network trigger. * No UAF, OOB write, double free, type confusion, refcount issue, or arbitrary write. * No privilege escalation plausibility. * No confidentiality or integrity impact. * No security-boundary bypass. The observed primitive is NULL dereference DoS only. ## 3. Reachability analysis The bug is locally reachable only if some actor can cause `dm_verity_loadpin_is_bdev_trusted()` to inspect a device-mapper block device that has no live table. In normal deployments, creating or manipulating that state requires CAP_SYS_ADMIN through device-mapper control paths, so the conservative interpretation is privileged local DoS. Namespaces or containers usually do not expose host device-mapper control to untrusted users, but some appliance or service configurations may delegate limited DM management, which justifies the paranoid score. The path is not network reachable. Call-site confidence: medium. The patch clearly shows the NULL dereference condition, but the exact external trigger path depends on product-specific LoadPin and device-mapper configuration. ## 4. Severity interpretation This behaves like an ordinary Moderate or Low-like kernel issue rather than an Important-class vulnerability. The theoretical impact is a kernel crash if the NULL table state is reached. Realistic exploitation evidence supports DoS only, not memory corruption, privilege escalation, information disclosure, or policy bypass. The issue does not require manual escalation unless the evaluated product exposes device-mapper control to less trusted local actors. ## 5. One-sentence report phrase A missing NULL check in the dm-verity LoadPin helper can let a local privileged or delegated device-mapper actor trigger a kernel NULL-pointer dereference when a DM device has no live table, causing denial of service only. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED This can be auto-closed for urgent triage because it is a local NULL-pointer DoS with typical admin-only reachability and no evidence of memory corruption, LPE, network exposure, or sensitive-object access. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: dm-verity: fix a possible NULL pointer dereference commit e72b793ae440f6900fb17a4b8518c707b5cd3e17 upstream. Commit: 7d4f1d307ac0f4f55cebeb192a90a235aa060ed1 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7d4f1d307ac0f4f55cebeb192a90a235aa060ed1 Commit description: Fix a possible NULL pointer dereference dm_verity_loadpin_is_bdev_trusted if the device has no table. Signed-off-by: Mikulas Patocka Assisted-by: Claude:claude-opus-4-6 Fixes: b6c1c5745ccc ("dm: Add verity helpers for LoadPin") Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman Diffstat -rw-r--r-- drivers/md/dm-verity-loadpin.c 2 Changed files: drivers/md/dm-verity-loadpin.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=7d4f1d307ac0f4f55cebeb192a90a235aa060ed1 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72097 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72097 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:H The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS score: 5.5 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: 0 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).