From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-98614][MODERATE REGULAR] sctp: avoid livelock while updating retransmit path [ Upstream Date: Sat, 24 Oct 2026 06:59:37 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-98614 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: 3 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: 3fe624c3843694ab096fdb198526ba0c659febbe List-Id: CVE: CVE-2026-98614 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: sctp: avoid livelock while updating retransmit path [ Upstream Commit: 3fe624c3843694ab096fdb198526ba0c659febbe Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3fe624c3843694ab096fdb198526ba0c659febbe Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98614 Analysis date: Sat, 24 Oct 2026 06:59:37 -0400 ActionableScore: 3 ActionableScore lower bound: unknown Actionable bucket: Borderline / manual review recommended Manual review required: YES Summary: A remotely influenced SCTP transport-state configuration can trap retransmission-path selection in an infinite loop, causing a kernel CPU stall without shown memory corruption. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-98614 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98614 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-2026-98614 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-98614 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=1 LEGACY=MODERATE RESULT=DIFF (final Legacy and Aegis differ; FINAL: MODERATE, Aegis: MODERATE_KPANIC) Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H';*CWE-835;**CWE-400;Other CVSS 'AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7.5';DESCR 'An SCTP logic error in sctp_assoc_update_retran_path can cause a livelock because SCTP_UNCONFIRMED transports are skipped before the iterator tests whether it returned to retran_path. If every remaining transport is UNCONFIRMED, kernel execution can remain in the walk and cause a CPU stall or watchdog soft lockup, resulting in denial of service without an identified memory corruption primitive. For the CVSS the PR:N value reflects that a network peer may interact with an existing SCTP association without credentials on the victim host, although reaching the required state depends on SCTP multihoming and path state transitions. Confidentiality and integrity are not affected based on the available code evidence, while availability can be high if the loop stalls kernel execution. Automated impact decision path. The original SimpleNet classifier selected MODERATE_KPANIC. The primary LLM estimated paranoid CVSS 7.5 and the production ActionableScore returned 3 with recommendation Borderline / manual review recommended. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were CVSS and initial triage stage MODERATE_KPANIC to MODERATE_KPANIC because the CVSS score, vector or bug class threshold rule was applied. ActionableScore thresholds stage MODERATE_KPANIC to MODERATE because the ActionableScore threshold rule was applied. The legacy KP specialist has no review artifact for this run. The legacy FD or DH downgrade specialist has no review artifact for this run. Exact triggered rule markers were INCREASED_TO_MODERATE7_BASED_ON_GUESSCVSS and DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 and V41_INHERITED_KPANIC_PROMOTION_BLOCKED and MANUAL_REVIEW_REQUIRED. The independent weaker Aegis shadow evaluated CVSS 3.7 and ActionableScore 1 with primitive class CLASS_C and manual review REQUIRED. Its independently reconciled impact was MODERATE_KPANIC. The models disagreed but the aggregation rules retained the production result. The final reported impact is MODERATE.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended (with actual score 3) MAYBE SIMPLEFIX NETWORK LINUS TEST INCREASED_TO_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 V41_INHERITED_KPANIC_PROMOTION_BLOCKED MANUAL_REVIEW_REQUIRED - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=3 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=UNKNOWN NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=NO ManualReview=RECOMMENDED AutoDowngradeAllowed=YES RequiresHostUID0=UNKNOWN AuthorizationDecisionBypass=NO ProtectedResourceImpact=NONE B4PendingReview=NO B4PendingConfirmed=NO 1. ActionableScore * Raw base score: 3. * Conservative score: 3; no floor or cap applied. * Raw paranoid score: 3. * Paranoid score: 3; no additional technically supported primitive. * Final recommended bucket: **Borderline / manual review recommended**:: 2. Signal breakdown * +2 Remote/net-reachable: an SCTP peer can plausibly influence an existing association’s transport states and retransmission-path update, although the complete all-UNCONFIRMED transition is not demonstrated by the patch. * +1 Reliable kernel DoS: the loop can fail to reach its wraparound check and run indefinitely, plausibly causing CPU stall or watchdog soft lockup. * No timing penalty: this is a deterministic state-dependent loop, not evidence of a narrow race. * No extra availability point: the stall/soft-lockup is the same DoS already counted. * No corruption points: the patch shows neither OOB access, UAF, stale-object mutation, nor attacker-controlled write. * NEW52/B5-R does not apply: there is no heap OOB write or retry-accumulated offset. * Authorization signals are not applicable; no DENY-to-ALLOW decision exists. 3. Reachability analysis A network peer may participate in SCTP association and path-state changes without local credentials. However, supplied code does not fully establish that the peer alone can force every remaining transport, including `retran_path`, into `SCTP_UNCONFIRMED` and invoke this update. Therefore effective host privilege and namespace scope remain unknown rather than proven host-admin-free. No special hardware or race is required; SCTP multihoming and the requisite path-state sequence are prerequisites. 4. Primitive and severity reading The exact defect is a loop-termination ordering error: `continue` bypasses the full-pass check for every unconfirmed transport. The secondary NULL guard prevents replacing an existing retransmit path with NULL, but no reachable NULL dereference is independently shown. This is CLASS_C availability behavior. The shown effect is livelock/CPU stall; memory corruption, confidentiality/integrity impact, authorization bypass, and useful post-crash leverage are unsupported. ImportantCandidate is NO and auto-downgrade is allowed because no unresolved corruption or security-boundary primitive remains. 5. One-sentence report phrase A remotely influenced SCTP transport-state configuration can trap retransmission-path selection in an infinite loop, causing a kernel CPU stall without shown memory corruption. 6. Manual review advice MANUAL CHECK RECOMMENDED Confirm whether an unauthenticated SCTP peer can reliably create the complete all-UNCONFIRMED state and trigger the update path. 7. Call-site confidence Call-site confidence: medium ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: sctp: avoid livelock while updating retransmit path [ Upstream Commit: 3fe624c3843694ab096fdb198526ba0c659febbe Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3fe624c3843694ab096fdb198526ba0c659febbe Changed files: net/sctp/associola.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=3fe624c3843694ab096fdb198526ba0c659febbe ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-98614 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98614 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:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS vector: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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: unknown Paranoid ActionableScore: 3 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).