From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-68288][LOW] net: drop_monitor: fix info leak in NET_DM_ATTR_PAYLOAD [ Upstream Date: Mon, 10 Aug 2026 13:06:58 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-68288 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: 1 X-AL-KERNEL-ActionableScore-Lower: 0 X-AL-KERNEL-Commit: 8fd6975d2aecc36b25ee82b6aef88e62a3527ccb List-Id: CVE: CVE-2026-68288 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: net: drop_monitor: fix info leak in NET_DM_ATTR_PAYLOAD [ Upstream Commit: 8fd6975d2aecc36b25ee82b6aef88e62a3527ccb Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8fd6975d2aecc36b25ee82b6aef88e62a3527ccb Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68288 Analysis date: Mon, 10 Aug 2026 13:06:58 -0400 ActionableScore: 1 ActionableScore lower bound: 0 Actionable bucket: Ordinary Moderate / Low-like Manual review required: NO Summary: drop_monitor may leak 1-3 bytes of uninitialized kernel padding in NET_DM_ATTR_PAYLOAD to a local netlink receiver when packet payload length is not 4 byte aligned, causing limited confidentiality impact only. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68288 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68288 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-2026-68288 LOW 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:L/UI:N/S:U/C:L/I:N/A:N';*CWE-200;CWE-201;CWE-908;*CWE-457;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N';BEST CVSS score: '3.3';DESCR 'drop_monitor can leak uninitialized kernel memory through NET_DM_ATTR_PAYLOAD because the code reserved nla_total_size(payload_len) bytes but copied only payload_len bytes of packet data. When payload_len is not 4 byte aligned, the netlink attribute padding can contain 1-3 uninitialized bytes and can be returned to userspace through netlink_recvmsg. For the CVSS the PR:L in the paranoid score is used because a local user may be able to receive already enabled drop_monitor netlink reports in some deployments, while configuring packet alert mode normally requires CAP_NET_ADMIN. The issue is not directly network reachable because the leaked bytes are delivered to a local netlink receiver, although remote traffic may influence which packet drops are reported. Impact is limited confidentiality exposure only. There is no evidence of memory corruption, denial of service, or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 1) YES REMOTE KASAN LEAK SKB HARDWARE LINUS PACKET NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=1 ActionableScoreLower=0 ## 1. ActionableScore * Conservative score: 0 * Paranoid score: 1 * Final recommended bucket: **Ordinary Moderate / Low-like**:: ## 2. Signal breakdown Conservative signals: * Confidentiality impact plausible: +1. The bug leaks 1-3 uninitialized kernel bytes from netlink attribute padding to userspace. * Requires admin/root/CAP_NET_ADMIN in typical deployments: -2. Configuring drop_monitor packet alert mode and receiving relevant diagnostic reports is typically privileged. * Rare AND difficult-to-reach subsystem/configuration: -1. drop_monitor packet alert mode is diagnostic functionality and not a default general networking receive path. Conservative result is floored to 0 for practical triage. Paranoid signals: * Local unprivileged trigger or receiver possibility: +1. In a permissive or already configured deployment, a local user may be able to receive drop_monitor netlink reports. * Confidentiality impact plausible: +1. The leak is real and confirmed by KMSAN. * Rare/config-dependent exposure: -1. The path depends on drop_monitor packet reporting being active and observable. No memory corruption, UAF, OOB write, privilege escalation, Dirty-Pipe-like primitive, or reliable DoS signal is supported by the patch. ## 3. Reachability analysis The leak is delivered through a local netlink receive path, not directly to a remote network attacker. Remote traffic may influence which packets are dropped and reported, but the leaked padding bytes are exposed only to a local process that can receive the drop_monitor message. In typical deployments, enabling or controlling drop_monitor packet alert mode requires CAP_NET_ADMIN, so the conservative interpretation treats this as privileged local diagnostic exposure. Namespaces could matter only if a product delegates relevant netlink or network administration permissions to less trusted users. ## 4. Severity interpretation This behaves like a low-end information disclosure issue, not an Important-class vulnerability. The primitive is limited to 1-3 uninitialized padding bytes per affected NET_DM_ATTR_PAYLOAD attribute when payload_len is not 4-byte aligned. There is no evidence of memory corruption, write capability, privilege escalation, kernel crash, or a remote readback path. The paranoid score only accounts for possible local unprivileged receipt in permissive configurations. ## 5. One-sentence report phrase drop_monitor may leak 1-3 bytes of uninitialized kernel padding in NET_DM_ATTR_PAYLOAD to a local netlink receiver when packet payload length is not 4 byte aligned, causing limited confidentiality impact only. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED The issue is a small confirmed local info leak with no memory corruption or privilege escalation primitive, and it is typically gated by privileged drop_monitor configuration. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: net: drop_monitor: fix info leak in NET_DM_ATTR_PAYLOAD [ Upstream Commit: 8fd6975d2aecc36b25ee82b6aef88e62a3527ccb Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8fd6975d2aecc36b25ee82b6aef88e62a3527ccb Changed files: net/core/drop_monitor.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=8fd6975d2aecc36b25ee82b6aef88e62a3527ccb ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68288 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68288 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:L/I:N/A:N The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N 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: 0 Paranoid ActionableScore: 1 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).