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actively exploited · CISA KEV

CVE-2026-67277

NVD HIGH 8.2 · published 2026-09-05 · 1 on the wire

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)

Exploited in the wild

Yes

CISA added it 2026-09-10. An observation, not a forecast.

EPSS · 30-day forecast

1%

Chance of exploitation in the next 30 days, 57th percentile of all CVEs. A forecast; KEV outranks it.

CVSS · NVD

8.2

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

Internet exposure

197,794

MikroTik hosts Shodan could see worldwide on 2026-09-07. A scan count, not an inventory.

On the wire1
References
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