{"cve":{"cve_id":"CVE-2026-67277","is_kev":true,"kev_date_added":"2026-09-10","kev_vendor_project":"MikroTik","kev_product":"RouterOS","kev_vulnerability_name":"MikroTik RouterOS Missing Authentication for Critical Function Vulnerability","kev_short_description":"MikroTik RouterOS contains a missing authentication for critical function vulnerability which allows kernel memory disclosure and denial of service in the btest service.","kev_required_action":"Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.","kev_due_date":"2026-09-13","kev_known_ransomware":false,"kev_notes":"https://mikrotik.com/supportsec/september-2026-vulnerability/ ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-67277","kev_cwes":["CWE-306"],"epss_score":0.00869,"epss_percentile":0.56832,"epss_as_of":"2026-09-15","description":"RouterOS accepts a \"related\" btest connection before the corresponding primary session has completed authentication. An unauthenticated client can use this state to start an IPv4 UDP test. With \"random-data=false\", the sender transmits an uninitialized tail from a kernel packet buffer. A separate unchecked, inverted packet-size interval causes unsigned integer underflow, anomalously large fragmented output, and can restart the RouterOS kernel.\n\n\n\nThis issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)","published_at":"2026-09-05T20:00:56.614000Z","last_modified_at":"2026-09-11T12:52:29.533000Z","cvss_v3_score":8.2,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","cvss_v3_severity":"HIGH","cvss_v4_score":8.8,"cvss_v4_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N","cvss_v4_severity":"HIGH","ssvc_decision":null,"ssvc_exploitation":null,"ssvc_automatable":null,"ssvc_technical_impact":null,"cwes":["CWE-306"],"nvd_references":["https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve","https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/","https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/","https://mikrotik.com/supportsec/september-2026-vulnerability/","https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802","https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801","https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800"],"vuln_status":"Analyzed","trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-09-05T22:34:30.385310Z","updated_at":"2026-09-12T23:45:47.139595Z"},"effective_severity":"HIGH","badges":["kev"],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"S","name":"Scope","value":"U","value_label":"Unchanged"},{"metric":"C","name":"Confidentiality","value":"L","value_label":"Low"},{"metric":"I","name":"Integrity","value":"N","value_label":"None"},{"metric":"A","name":"Availability","value":"H","value_label":"High"}]},"cvss_v4_decoded":{"version":"4.0","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"AT","name":"Attack Requirements","value":"N","value_label":"None"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"VC","name":"Confidentiality (Vulnerable System)","value":"L","value_label":"Low"},{"metric":"VI","name":"Integrity (Vulnerable System)","value":"N","value_label":"None"},{"metric":"VA","name":"Availability (Vulnerable System)","value":"H","value_label":"High"},{"metric":"SC","name":"Confidentiality (Subsequent System)","value":"N","value_label":"None"},{"metric":"SI","name":"Integrity (Subsequent System)","value":"N","value_label":"None"},{"metric":"SA","name":"Availability (Subsequent System)","value":"N","value_label":"None"}]},"affected":[{"vendor_slug":"mikrotik","vendor_name":"MikroTik","product_slug":"routeros","product_name":"RouterOS","version_start":"7.24","version_start_inclusive":true,"version_end":"7.24.2","version_end_inclusive":false,"cpe23_uri":"cve5:mikrotik:routeros:7.24:7.24.2"},{"vendor_slug":"mikrotik","vendor_name":"MikroTik","product_slug":"routeros","product_name":"RouterOS","version_start":"7.0.0","version_start_inclusive":true,"version_end":"7.23.4","version_end_inclusive":false,"cpe23_uri":"cve5:mikrotik:routeros:7.0.0:7.23.4"},{"vendor_slug":"mikrotik","vendor_name":"MikroTik","product_slug":"routeros","product_name":"RouterOS","version_start":"6.0.0","version_start_inclusive":true,"version_end":"6.49.21","version_end_inclusive":false,"cpe23_uri":"cve5:mikrotik:routeros:6.0.0:6.49.21"},{"vendor_slug":"mikrotik","vendor_name":"MikroTik","product_slug":"routeros","product_name":"RouterOS","version_start":"6.0","version_start_inclusive":true,"version_end":"6.49.21","version_end_inclusive":false,"cpe23_uri":"cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*"}],"exploit_refs":[],"news":[],"references":[{"url":"https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve","source_type":"MISC","tags":[]},{"url":"https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/","source_type":"MISC","tags":[]},{"url":"https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/","source_type":"MISC","tags":["patch"]},{"url":"https://mikrotik.com/supportsec/september-2026-vulnerability/","source_type":"MISC","tags":[]},{"url":"https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802","source_type":"MISC","tags":[]},{"url":"https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801","source_type":"MISC","tags":[]},{"url":"https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800","source_type":"MISC","tags":[]}],"timeline":[{"type":"published","at":"2026-09-05T20:00:56.614000Z","label":"CVE published","source":null},{"type":"cisa_reported","at":"2026-09-10T00:00:00Z","label":"Added to CISA KEV catalog","source":"kev"},{"type":"cvss_changed","at":"2026-09-12T23:45:47.139595Z","label":"CVSS score revised","source":"nvd"},{"type":"cvss_changed","at":"2026-09-12T23:45:47.139595Z","label":"CVSS score revised","source":"nvd"},{"type":"cvss_changed","at":"2026-09-12T23:45:47.139595Z","label":"CVSS score revised","source":"nvd"}]}