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.
This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)
"}],"value":"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)"}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":8.8,"baseSeverity":"HIGH","exploitMaturity":"NOT_DEFINED","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"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","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-306","description":"CWE-306 Missing authentication for critical function","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-09-05T20:39:44.166Z","orgId":"4bb8329e-dd38-46c1-aafb-9bf32bcb93c6","shortName":"CERT-PL"},"references":[{"tags":["third-party-advisory"],"url":"https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve"},{"tags":["technical-description"],"url":"https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/"},{"tags":["exploit"],"url":"https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/"},{"tags":["vendor-advisory"],"url":"https://mikrotik.com/supportsec/september-2026-vulnerability/"},{"tags":["release-notes"],"url":"https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802"},{"tags":["release-notes"],"url":"https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801"},{"tags":["release-notes"],"url":"https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800"}],"source":{"discovery":"INTERNAL"},"title":"Kernel memory disclosure and denial of service in MikroTik RouterOS btest service","x_generator":{"engine":"Vulnogram 1.0.3"}}},"cveMetadata":{"assignerOrgId":"4bb8329e-dd38-46c1-aafb-9bf32bcb93c6","assignerShortName":"CERT-PL","cveId":"CVE-2026-67277","datePublished":"2026-09-05T20:00:56.614Z","dateReserved":"2026-07-29T11:59:30.538Z","dateUpdated":"2026-09-05T20:39:44.166Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-05 20:17:18","lastModifiedDate":"2026-09-05 21:16:50","problem_types":["CWE-306","CWE-306 CWE-306 Missing authentication for critical function"],"metrics":{"cvssMetricV40":[{"source":"cvd@cert.pl","type":"Secondary","cvssData":{"version":"4.0","vectorString":"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","baseScore":8.8,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"67277","Ordinal":"1","Title":"Kernel memory disclosure and denial of service in MikroTik Route","CVE":"CVE-2026-67277","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"67277","Ordinal":"1","NoteData":"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)","Type":"Description","Title":"Kernel memory disclosure and denial of service in MikroTik Route"}]}}}