From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-74698][LOW] net/mlx5e: fix BQL reset on SQ re-activation [ Upstream Date: Sat, 22 Aug 2026 17:22:10 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-74698 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: 88664c48d7d1eca8e1ac92da85c89c26af741cf1 List-Id: CVE: CVE-2026-74698 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: net/mlx5e: fix BQL reset on SQ re-activation [ Upstream Commit: 88664c48d7d1eca8e1ac92da85c89c26af741cf1 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=88664c48d7d1eca8e1ac92da85c89c26af741cf1 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74698 Analysis date: Sat, 22 Aug 2026 17:22:10 -0400 ActionableScore: 1 ActionableScore lower bound: 0 Actionable bucket: Ordinary Moderate / Low-like Manual review required: NO Summary: mlx5e could reset BQL accounting while TX WQEs were still in flight, causing a later TX completion to trip BUG_ON() in dql_completed() and crash the kernel, but triggering typically requires local network device administration privileges. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-74698 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74698 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-2026-74698 LOW CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';CWE-617;CWE-667;CWE-703;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '4.7';DESCR 'mlx5e can reset BQL accounting while TX WQEs are still in flight during SQ re activation. The next TX completion can then over charge the dynamic queue limit accounting and hit BUG_ON() in dql_completed(), causing a kernel crash or panic in IRQ or NAPI context. For the CVSS the PR:L is used in the paranoid score because some deployments may delegate network device control to a reduced capability root, container root, or service account with CAP_NET_ADMIN like permissions. The normal case is closer to PR:H because queue management and driver reconfiguration are administrative operations. The issue is not directly network reachable. Remote traffic may help keep TX work outstanding, but the vulnerable transition is triggered through local control plane queue re activation. Impact is denial of service only. No UAF, OOB access, information leak, or privilege escalation primitive is indicated by the code change.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 1) SKIP CVE-2026-74698 UNKNOWN SKIP No affected files built, so skip this CVE NO - - unknown MAYBE REMOTE DANGER NETWORK DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 - - 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: * Reliable kernel crash / strong DoS: +1. The commit shows a concrete BUG_ON() in dql_completed() after BQL accounting is reset while TX WQEs are still in flight. * Requires admin/root/CAP_NET_ADMIN in typical deployments: -2. The vulnerable transition is SQ re-activation / queue management, normally requiring administrative network device control. * Hard or unreliable timing / state condition: -1. Triggering requires queue re-activation while another SQ still has in-flight TX WQEs. Paranoid adjustment: * Reduced-capability network administration scenario: +1 relative to conservative handling. In containerized or delegated environments, a service account, container root, or reduced-capability root with CAP_NET_ADMIN-like control may be able to trigger the reset path without full host-root equivalence. Not applied: * No remote reachable signal. Network traffic may help keep TX WQEs in flight, but the vulnerable state transition is local control-plane queue re-activation. * No memory corruption signal. The patch shows BQL/DQL accounting inconsistency leading to BUG_ON(), not UAF, OOB write, double free, type confusion, or attacker-controlled overwrite. * No privilege escalation signal. There is no supported LPE primitive. * No confidentiality or integrity signal. The demonstrated effect is availability only. ## 3. Reachability analysis The bug is reachable through mlx5e queue management / SQ re-activation paths on systems using Mellanox mlx5 Ethernet hardware. In normal deployments, triggering requires local administrative control over the network device or driver state, so the conservative privilege model is high privilege. Namespaces or containers can matter if network administration is delegated. A container root or service account with enough control over the relevant netdev could lower the practical privilege requirement, but this is deployment-dependent and does not make the issue unprivileged by default. The path is not directly network-triggerable. Remote traffic can contribute to having outstanding TX WQEs, but cannot by itself invoke the queue re-activation sequence shown in the patch. ## 4. Severity interpretation This behaves like an ordinary Moderate or Low-like kernel DoS issue. The crash is concrete and credible, but the trigger is privileged, state-dependent, hardware-specific, and limited to availability impact. Theoretical memory corruption potential is not supported by the patch. The evidence points to an accounting mismatch that reaches a defensive BUG_ON(), not to stale object reuse, write-after-free, arbitrary write, or privilege escalation. ## 5. One-sentence report phrase mlx5e could reset BQL accounting while TX WQEs were still in flight, causing a later TX completion to trip BUG_ON() in dql_completed() and crash the kernel, but triggering typically requires local network device administration privileges. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED This is a local privileged DoS with a clear BUG_ON() failure mode and no evidence of memory corruption, information disclosure, integrity impact, or privilege escalation. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: net/mlx5e: fix BQL reset on SQ re-activation [ Upstream Commit: 88664c48d7d1eca8e1ac92da85c89c26af741cf1 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=88664c48d7d1eca8e1ac92da85c89c26af741cf1 Changed files: lib/dynamic_queue_limits.c drivers/net/ethernet/mellanox/mlx5/core/en_main.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=88664c48d7d1eca8e1ac92da85c89c26af741cf1 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-74698 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74698 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:H/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS score: 4.7 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).