CVE-2026-67277
Kernel memory disclosure and denial of service in MikroTik RouterOS btest service
CVSS Score
0.0
EPSS Score
0.0%
EPSS Percentile
0th
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)
| CWE | CWE-306 |
| Vendor | mikrotik |
| Product | routeros |
| Published | Sep 5, 2026 |
| Last Updated | Sep 11, 2026 |
⚠️ Actively Exploited — Act Now
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Affected Versions
Mikrotik / RouterOS
7.24 < 7.24.2 7.0.0 < 7.23.4 6.0.0 < 6.49.21
References
cert.pl: https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve cert.pl: https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/ npratley.net: https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/ mikrotik.com: https://mikrotik.com/supportsec/september-2026-vulnerability/ forum.mikrotik.com: https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802 forum.mikrotik.com: https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801 forum.mikrotik.com: https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800 cisa.gov: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-67277
Credits
Sławomir Rozbicki (CERT.PL)