From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-72447][MODERATE REGULAR] sctp: hold socket lock when dumping endpoints in sctp_diag [ Upstream Date: Sat, 15 Aug 2026 10:58:46 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-72447 X-AL-KERNEL-Priority: MODERATE REGULAR X-AL-KERNEL-Severity: MODERATE REGULAR X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 4 X-AL-KERNEL-ActionableScore-Lower: 3 X-AL-KERNEL-Commit: f98c294a9369b6fe89e652c06357ee594be4dfa2 List-Id: CVE: CVE-2026-72447 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: sctp: hold socket lock when dumping endpoints in sctp_diag [ Upstream Commit: f98c294a9369b6fe89e652c06357ee594be4dfa2 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f98c294a9369b6fe89e652c06357ee594be4dfa2 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72447 Analysis date: Sat, 15 Aug 2026 10:58:46 -0400 ActionableScore: 4 ActionableScore lower bound: 3 Actionable bucket: Actionable Moderate at minimum Manual review required: YES Summary: SCTP_DIAG endpoint dumping can race with concurrent SCTP address list updates, causing netlink dumps to expose uninitialized kernel memory to a local user through a count versus copy mismatch. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72447 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72447 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 REGULAR 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-2026-72447 MODERATE CHECK WITH IMPACT FROM ORIG NN IMPORTANT Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:L';CWE-362;*CWE-200;CWE-908;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N';BEST CVSS score: '5.3';DESCR 'SCTP_DIAG endpoint dumping can race with socket address list updates such as bindx because endpoint address lists were read without lock_sock(). The race can make the netlink dump reserve space for one address count and then copy fewer entries, which can expose uninitialized kernel memory to local userspace. For the CVSS the PR:L is used because triggering requires a local process able to issue SCTP_DIAG netlink requests and race them with socket operations, but full administrator privileges are not required in common configurations. The issue is not directly network reachable because it is triggered through local diagnostic netlink control plane operations rather than remote SCTP packets. Impact is primarily confidentiality loss from a local information leak. Availability impact is limited but possible if inconsistent state triggers warnings or repeated failed dumps. YES REQUIRES MANUAL CHECK.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 4) YES REMOTE OOB RACE LEAK UAF NETWORK SKB LINUS LOWERED_FROM_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=4 ActionableScoreLower=3 ## 1. ActionableScore * Conservative score: 3 * Paranoid score: 4 * Final recommended bucket: **Actionable Moderate at minimum** ## 2. Signal breakdown Conservative signals: * Local unprivileged trigger: +1. A local process can issue SCTP_DIAG netlink dump requests and race them with SCTP socket address changes such as bindx. * Confidentiality impact plausible: +1. The commit explicitly describes a count versus copy race that may leak uninitialized kernel memory to userspace. * Local netlink high-control diagnostic path: +1. The attacker can shape endpoint address list state and repeatedly request structured netlink dumps. * Memory layout invariant restoration: +1. The bug is a mismatch between address counting, nla_reserve sizing, and later address copying in a networking message construction path. * Hard or unreliable race: -1. Reliable exploitation requires winning a timing window between address list mutation and diagnostic dumping. Paranoid additional signal: * Practical leak chain strongly implied: +1. The commit gives a concrete mechanism: reserve for more addresses than are copied, leaving uninitialized payload visible in the netlink response. ## 3. Reachability analysis The bug is local, not remotely reachable through SCTP packets. The trigger is the SCTP diagnostic netlink path combined with concurrent SCTP socket operations such as bindx. Typical triggering does not require full administrator privileges, although exact visibility and fields may depend on netlink permissions and namespace policy. Network namespaces may make the path reachable to containerized or namespace-local users if SCTP and sock_diag are available. Exploitation requires a race, but the affected objects are ordinary socket endpoint address lists, so repeated attempts are realistic. Call-site confidence: high. The patch includes both the dump path and the endpoint traversal helper. ## 4. Severity interpretation This behaves more like an actionable Moderate than an ordinary low-risk cleanup. The supported primitive is an uninitialized kernel memory disclosure to local userspace, not UAF, OOB write, arbitrary write, or direct LPE. Theoretical escalation through leaked kernel data is possible in broader exploit chains, but the patch itself supports confidentiality impact rather than integrity impact or privilege escalation. It should not be scored as Important solely from the race, but it also should not be auto-closed as a harmless DoS or correctness issue. ## 5. One-sentence report phrase SCTP_DIAG endpoint dumping can race with concurrent SCTP address list updates, causing netlink dumps to expose uninitialized kernel memory to a local user through a count versus copy mismatch. ## 6. Manual review recommendation MANUAL CHECK REQUIRED A concrete local kernel memory disclosure primitive is described, and the issue was reported through a security research channel. Manual review is needed to determine practical leak quality, namespace exposure, and whether leaked data can assist further exploitation. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: sctp: hold socket lock when dumping endpoints in sctp_diag [ Upstream Commit: f98c294a9369b6fe89e652c06357ee594be4dfa2 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f98c294a9369b6fe89e652c06357ee594be4dfa2 Changed files: include/net/sctp/sctp.h net/sctp/diag.c net/sctp/socket.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=f98c294a9369b6fe89e652c06357ee594be4dfa2 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72447 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72447 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:L/UI:N/S:U/C:L/I:N/A:N The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:L The Best / paranoid CVSS score: 5.3 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: 3 Paranoid ActionableScore: 4 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: NO Published priority for this report (same as in Subject): MODERATE REGULAR 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).