From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-80714][MODERATE 7.0] ipvs: do not propagate one-packet flag to synced conns Date: Fri, 28 Aug 2026 06:19:42 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-80714 X-AL-KERNEL-Priority: MODERATE 7.0 X-AL-KERNEL-Severity: MODERATE 7.0 X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: YES X-AL-KERNEL-ActionableScore: 7 X-AL-KERNEL-ActionableScore-Lower: 5 X-AL-KERNEL-Commit: 06d1d9b56ef8132fbf85006885eb43d9510b8b02 List-Id: CVE: CVE-2026-80714 Priority: MODERATE 7.0 AL-KERNEL base severity: MODERATE KPANIC flag: YES Patch: ipvs: do not propagate one-packet flag to synced conns Commit: 06d1d9b56ef8132fbf85006885eb43d9510b8b02 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=06d1d9b56ef8132fbf85006885eb43d9510b8b02 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80714 Analysis date: Fri, 28 Aug 2026 06:19:42 -0400 ActionableScore: 7 ActionableScore lower bound: 5 Actionable bucket: Strong Important candidate / Actionable Moderate at minimum Manual review required: YES Summary: An IPVS synced connection can incorrectly inherit IP_VS_CONN_F_ONE_PACKET, causing expiry to skip unlinking an already hashed connection and leaving stale conn_tab nodes pointing to a freed struct ip_vs_conn, which is at least a network-adjacent DoS and a UAF candidate requiring manual review. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-80714 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80714 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 7.0 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-2026-80714 MODERATE CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H';*CWE-416;*CWE-672;*CWE-664;Other CVSS 'AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7.5';DESCR 'An IPVS synced connection can incorrectly inherit IP_VS_CONN_F_ONE_PACKET from a destination that is bound later. Because synced connections are already hashed, expiry can treat such an entry as a one-packet connection and skip unlinking the existing conn_tab node. This leaves a stale hash node that points to a freed struct ip_vs_conn and creates a use-after-free candidate in the IPVS connection table. For the CVSS the PR:N value is used because an attacker with access to the IPVS sync or LVS cluster network may not need local privileges on the victim. The issue is network adjacent rather than Internet remote in typical deployments because IPVS sync traffic is normally limited to trusted load balancer networks. Impact is at least denial of service via crash or corrupted IPVS state. In the worst case, stale references to freed kernel connection objects may allow confidentiality or integrity impact through memory corruption and should be reviewed manually.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 7) YES REMOTE NETFILTER UAF KPANIC KPANIC INCREASED_TO_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFKP NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=7 ActionableScoreLower=5 ## 1. ActionableScore * Conservative score: 5 * Paranoid score: 7 * Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**:: ## 2. Signal breakdown Conservative scoring: * Remote reachable / network-triggerable: +2. Trigger is realistically network-adjacent through IPVS sync or LVS cluster traffic, not ordinary Internet remote exposure. * Memory corruption, weak/indirect corruption candidate: +1. The commit explicitly describes stale hash nodes pointing at a freed `struct ip_vs_conn`, but does not demonstrate controlled reclaim or attacker-controlled replacement. * Real lifetime corruption: +1. This is a stale pointer after free / UAF candidate in the IPVS connection table. * Reliable kernel crash / strong DoS: +1. Later lookup, expiry, or traversal of the stale hash node can plausibly crash or corrupt IPVS state. * Hard or configuration-specific trigger: -1. Requires synced connections, later destination binding, and one-packet flag inheritance in a specific IPVS setup. Paranoid scoring: * Remote reachable / network-triggerable: +2. * Memory corruption, strong corruption primitive: +2. Paranoid interpretation treats the stale hash node to freed `ip_vs_conn` as a real UAF primitive requiring manual review. * Real lifetime corruption: +1. * Reliable kernel crash / strong DoS: +1. * Weak LPE concern: +1. Not proven, but freed connection objects remaining reachable from a hash table may enable unsafe reuse scenarios. * Availability impact realistic: +1. The stale hash entry can persist beyond the original expiry event and affect later IPVS connection table operations. * Hard or configuration-specific trigger: -1. ## 3. Reachability analysis The likely attacker needs access to the IPVS sync or LVS cluster network, or another way to influence synced connection state. This is not a generic public Internet packet path in typical deployments. IPVS sync traffic is usually restricted to trusted load balancer or HA networks. No local privilege on the victim is necessarily required if the attacker can inject or influence sync traffic. However, configuring IPVS itself normally requires administrative privileges. Containers or namespaces matter mainly if they expose IPVS administration or sync interfaces to less trusted actors. The path is configuration-dependent because IPVS sync and one-packet scheduling must be in use. The issue is still security-relevant because the commit explicitly describes stale hash nodes pointing to freed kernel connection objects. ## 4. Severity interpretation This is stronger than ordinary Moderate because the patch context identifies a concrete kernel lifetime error: a stale hash node can point to a freed `struct ip_vs_conn`. Realistic demonstrated impact is DoS or IPVS state corruption. Practical privilege escalation is not demonstrated. The paranoid score treats the stale reachable freed object as a UAF candidate that could have confidentiality or integrity implications if later object reuse is controllable. This makes it a Strong Important candidate for manual review, while the conservative view is Actionable Moderate. ## 5. One-sentence report phrase An IPVS synced connection can incorrectly inherit IP_VS_CONN_F_ONE_PACKET, causing expiry to skip unlinking an already hashed connection and leaving stale conn_tab nodes pointing to a freed struct ip_vs_conn, which is at least a network-adjacent DoS and a UAF candidate requiring manual review. ## 6. Manual review recommendation MANUAL CHECK REQUIRED Reason: the patch explicitly describes stale hash nodes pointing at freed `struct ip_vs_conn` objects. This is a real lifetime corruption pattern and should not be auto-closed as a simple DoS-only bug. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: ipvs: do not propagate one-packet flag to synced conns Commit: 06d1d9b56ef8132fbf85006885eb43d9510b8b02 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=06d1d9b56ef8132fbf85006885eb43d9510b8b02 Commit description: Synced connections can be created before their destination exists. When the destination is later added, ip_vs_bind_dest() copies connection flags from the destination into cp->flags. IP_VS_CONN_F_ONE_PACKET connections are not synced. If a synced connection inherits IP_VS_CONN_F_ONE_PACKET while it is already hashed, expiry can treat it as a one-packet connection and skip unlinking the existing conn_tab node, leaving stale hash nodes pointing at a freed struct ip_vs_conn. Drop IP_VS_CONN_F_ONE_PACKET from destination flags when binding synced connections. Fixes: 26ec037 ("IPVS: one-packet scheduling") Cc: stable@vger.kernel.org Reported-by: Yuan Tan Reported-by: Yifan Wu Reported-by: Juefei Pu Reported-by: Xin Liu Suggested-by: Julian Anastasov Signed-off-by: Zhiling Zou Signed-off-by: Ren Wei Acked-by: Julian Anastasov Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman Changed files: net/netfilter/ipvs/ip_vs_conn.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=06d1d9b56ef8132fbf85006885eb43d9510b8b02 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-80714 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80714 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:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS vector: AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H The Best / paranoid CVSS score: 7.5 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: 5 Paranoid ActionableScore: 7 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: YES Published priority for this report (same as in Subject): MODERATE 7.0 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).