{"id":"CVE-2026-67277","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-67277","generatedAt":"2026-10-31T04:00:52.019Z","title":"MikroTik RouterOS Missing Authentication for Critical Function Vulnerability","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":"2026-09-05T20:17:18.000Z","lastModified":"2026-09-11T12:52:30.000Z","status":"Analyzed","sourceIdentifier":"cvd@cert.pl","cvss":{"version":"4.0","score":8.8,"severity":"HIGH","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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-306"],"affected":["mikrotik/routeros"],"epss":{"score":0.0156,"percentile":0.75209,"date":"2026-10-30","history":[]},"kev":{"listed":true,"dateAdded":"2026-09-10","dueDate":"2026-09-13","knownRansomwareCampaignUse":"Unknown","notes":"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.\nhttps://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"},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"Known to be exploited in the wild (CISA KEV, CISA remediation deadline 13 September 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise."},"changes":[],"references":[{"url":"https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve","tags":["Third Party Advisory"],"source":"cvd@cert.pl"},{"url":"https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/","tags":["Mitigation","Third Party Advisory"],"source":"cvd@cert.pl"},{"url":"https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802","tags":["Release Notes"],"source":"cvd@cert.pl"},{"url":"https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801","tags":["Release Notes"],"source":"cvd@cert.pl"},{"url":"https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800","tags":["Release Notes"],"source":"cvd@cert.pl"},{"url":"https://mikrotik.com/supportsec/september-2026-vulnerability/","tags":["Vendor Advisory"],"source":"cvd@cert.pl"},{"url":"https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/","tags":["Exploit","Third Party Advisory"],"source":"cvd@cert.pl"},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-67277","tags":["US Government Resource"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-67277","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}