{"schema_version":"0.10.0","id":"LR-2026-0727","record_version":1,"title":"XBOW autonomous agent finds Linux kernel DIBS loopback flaw enabling local root (CVE-2026-72018)","verification":{"human_verified":false,"method":"automated_gate","auto_verified":true,"score":46.6,"score_breakdown":{"source_authority":12.1,"independent_corroboration":7.0,"implicated_party_confirmed":0.0,"citation_integrity":14.0,"specificity":3.0,"completeness":3.2,"unhedged_language":5.0},"checks":{"schema_valid":true,"every_field_cited":true,"quotes_verbatim":true,"source_fetched":true,"distinct_incident":true,"dates_plausible":true,"sources_agree":true,"source_describes_incident":true,"severe_backed_by_source":true,"record_integrity":true,"eligible":true,"about_this_case":true},"gate_version":"gate-2026-10-18.7","cross_check_model":null,"cross_check_agreement":null,"duplicate_of":null,"verified_by":null,"verified_at":"2026-11-01","extraction_run_id":null,"evidence_level":{"level":"preliminary","reason":"1 report: Cyber Security News · subject to change","original_document":null,"reports_total":1,"reports_independent":1,"reports_derivative":0,"developing":false,"disputed":false,"rules_version":"evidence-2026-10-29.1","computed_at":"2026-11-01","history":[{"date":"2026-11-01","from_level":null,"to_level":"preliminary","reason":"1 report: Cyber Security News · subject to change"}]},"sources_hash":"286416a589cbbe11a823544bf2ce581781aa3ba46923d12b030b5e70623e6199"},"system":{"model_name":null,"model_version":null,"developer":"XBOW","harness":null,"tools_granted":[],"permissions_scope":null,"autonomy_level":"unknown","guardrails_present":[],"deployment_context":"unknown","tier":null,"lifecycle_stage":null,"integration_type":null,"intended_use":null,"safeguard_state":null,"production_intended":null},"event":{"date_occurred":null,"date_disclosed":"2026-09-30","incident_class":"other","failure_class":null,"agent_involved":true,"secondary_failure_classes":[],"trigger":"unknown","duration":null,"detection_method":"unknown","summary":"XBOW, an autonomous security research platform, had its agent handle threat modeling, code auditing, bug discovery, validation and much of exploit development against the Linux kernel. The agent identified a missing bounds check in the DIBS loopback driver used by SMC-D, which allowed a copy beyond an allocated kernel buffer. The researchers built a local privilege-escalation exploit from a weak 16-byte zero write, and the reported proof of concept reached root on 22 of 100 boots in a test on Ubuntu 24.04 with mitigations disabled. The flaw was disclosed as CVE-2026-72018, and an upstream fix adds offset and size validation. Human researchers redirected the agent at several points. Administrators are advised to apply the kernel update and review CAP_NET_ADMIN grants.","tags":[],"date_detected":null,"near_miss":null,"root_cause":null,"root_cause_detail":null,"failure_class_detail":null,"responsible_party":null,"adversarial_actor":null,"input_provenance":null,"time_to_contain":null,"operations_paused":null,"remediation":"Upstream remediation adds validation for offset and size before the copy operation.","precursor_events":null,"primary_risk":"RK07"},"impact":{"direct_loss_usd":null,"remediation_hours":null,"records_exposed":null,"third_parties_affected_count":null,"severity":"minor","severity_because":"minor: the exploit work was contained to one experiment on Ubuntu 24.04 with kernel mitigations disabled, and no third party is stated as touched","harm_class":[],"affected_description":null,"protected_class_involved":null,"data_categories_exposed":[],"loss_range_usd":null,"reversibility":null,"downstream_exposure_count":null},"evidence":{"sources":[{"url":"https://cybersecuritynews.com/ai-agent-finds-linux-kernel-bug/","publisher":"CyberSecurityNews","date":"2026-09-30","type":"press","title":"AI Agent Finds Linux Kernel Bug That Turns a Tiny Memory Write Into Root Access - CyberSecurityNews","archived_url":null,"attachment":"first_report","independence":"independent"}],"per_field_confidence":{"system.developer":"C","event.agent_involved":"C","event.remediation":"C","event.incident_class":"D","impact.severity_because":"D","impact.severity":"D","event.primary_risk":"D","event.summary":"C","system.autonomy_level":"D","system.deployment_context":"D","event.trigger":"D","event.detection_method":"D","context.country":"D","event.date_disclosed":"D","context.denominator_available":"D"},"field_citations":{"system.developer":[{"source_index":0,"quote":"Autonomous security research platform XBOW has disclosed CVE-2026-72018, a high-severity Linux kernel vulnerability that converts a tightly constrained out-of-bounds memory write into local root access."}],"event.agent_involved":[{"source_index":0,"quote":"XBOW said its agent handled threat modeling, code auditing, bug discovery, validation, and much of the exploit-development process."}],"event.remediation":[{"source_index":0,"quote":"The upstream remediation adds validation for offset and size before the copy operation."}],"event.incident_class":[{"source_index":0,"quote":"XBOW said its agent handled threat modeling, code auditing, bug discovery, validation, and much of the exploit-development process."}],"impact.severity_because":[{"source_index":0,"quote":"The experiment was performed on Ubuntu 24.04 using Linux 7.1.0-rc6 with kernel mitigations disabled, so that real-world reliability may differ across distributions, kernel builds, allocator behavior, and enabled mitigations."}],"impact.severity":[{"source_index":0,"quote":"The experiment was performed on Ubuntu 24.04 using Linux 7.1.0-rc6 with kernel mitigations disabled, so that real-world reliability may differ across distributions, kernel builds, allocator behavior, and enabled mitigations."}],"event.summary":[{"source_index":0,"quote":"XBOW said its agent handled threat modeling, code auditing, bug discovery, validation, and much of the exploit-development process."},{"source_index":0,"quote":"The flaw affects the DIBS loopback implementation used by the SMC-D shared-memory communication path, where a missing bounds check allows attacker-controlled data to be copied beyond an allocated kernel buffer."},{"source_index":0,"quote":"Despite this limitation, the researchers developed a local privilege-escalation exploit that elevated a process to root without requiring a separate information leak."},{"source_index":0,"quote":"XBOW reported that its proof of concept succeeded on 22 out of 100 separate boots, with the first successful privilege escalation appearing on the seventh boot."},{"source_index":0,"quote":"The upstream remediation adds validation for offset and size before the copy operation."},{"source_index":0,"quote":"However, human researchers made several important interventions."},{"source_index":0,"quote":"Administrators should apply Linux kernel updates containing the DIBS loopback bounds-check fix and reboot affected systems."}]},"notes_on_gaps":"Single press source (CyberSecurityNews) reporting XBOW's own claims; no independent or government evaluation. This is a vulnerability disclosure from research, not a production incident; no harm to third parties is stated. Not stated: date of occurrence, the exact disclosure date (the article is dated 2026-09-30 but that is the article date, so date_disclosed and date_detected were left out), detection method, trigger, adversarial actor, autonomy level, system model name and version, harness, tools granted, and guardrails. No agent misbehaviour is reported, so failure_class and related fields were left out. root_cause was left out because the closed list does not fit a software bounds-check flaw; the detail is kept in root_cause_detail. No controls are stated as held, failed or got around in this incident, so links is empty. Severity 'minor' is my judgement under the test: contained to one experiment, no third party touched. Harm_class none_materialised is my judgement from the stated experiment setting. Remediation J1 and A1 are my mapping of the stated changes and advice. The promotional line in the source was ignored. [case created by the backfill: read by claude-haiku-5-5, backfill-2026-11-01.2, 2026-11-01; not yet reviewed] [2026-11-01: evidence level set: Preliminary (1 report: Cyber Security News · subject to change)]"},"context":{"industry":null,"org_size_band":null,"country":"unknown","denominator_available":false,"denominator":null,"related_incident_ids":[],"systemic_exposure":null,"shared_model_id":null,"upstream_incident_id":null,"incident_evidence":null,"regulatory":null,"coverage":null},"narrative":{"steps":[{"step":"doing","text":"XBOW's autonomous agent handled threat modeling, code auditing, bug discovery, validation, and much of exploit development against the Linux kernel.","quote":"XBOW said its agent handled threat modeling, code auditing, bug discovery, validation, and much of the exploit-development process.","source_index":0,"grade":"C"},{"step":"went_wrong","text":"A missing bounds check in the DIBS loopback driver let attacker-controlled data be copied beyond an allocated kernel buffer.","quote":"The flaw affects the DIBS loopback implementation used by the SMC-D shared-memory communication path, where a missing bounds check allows attacker-controlled data to be copied beyond an allocated kernel buffer.","source_index":0,"grade":"C"},{"step":"done","text":"Administrators are advised to apply the kernel update with the bounds-check fix and reboot affected systems.","quote":"Administrators should apply Linux kernel updates containing the DIBS loopback bounds-check fix and reboot affected systems.","source_index":0,"grade":"C"}],"model":"claude-haiku-5-5","prompt_version":"backfill-2026-11-01.2","extracted_at":"2026-11-01","source_urls":["https://cybersecuritynews.com/ai-agent-finds-linux-kernel-bug/"]},"analysis":{"sections":{"timeline":[{"text":"The proof of concept succeeded on 22 of 100 boots, with the first escalation on the seventh boot.","quote":"XBOW reported that its proof of concept succeeded on 22 out of 100 separate boots, with the first successful privilege escalation appearing on the seventh boot.","source_index":0,"when":null},{"text":"Upstream remediation added offset and size validation before the copy operation.","quote":"The upstream remediation adds validation for offset and size before the copy operation.","source_index":0,"when":null},{"text":"Administrators were advised to apply the kernel updates and reboot affected systems.","quote":"Administrators should apply Linux kernel updates containing the DIBS loopback bounds-check fix and reboot affected systems.","source_index":0,"when":null}]},"model":"claude-haiku-5-5","prompt_version":"backfill-2026-11-01.2","extracted_at":"2026-11-01","source_urls":["https://cybersecuritynews.com/ai-agent-finds-linux-kernel-bug/"]}}