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.



This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)
Published: 2026-09-05
Score: 8.8 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Sat, 05 Sep 2026 20:45:00 +0000

Type Values Removed Values Added
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. This issue was fixed in versions: 6.49.21 (Lont-term), 7.23.4 (Lont-term) and 7.24.2 (Stable) 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)

Sat, 05 Sep 2026 20:15:00 +0000

Type Values Removed Values Added
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. This issue was fixed in versions: 6.49.21 (Lont-term), 7.23.4 (Lont-term) and 7.24.2 (Stable)
Title Kernel memory disclosure and denial of service in MikroTik RouterOS btest service
First Time appeared Mikrotik
Mikrotik routeros
Weaknesses CWE-306
CPEs cpe:2.3:a:mikrotik:routeros:*:*:*:*:*:*:*:*
Vendors & Products Mikrotik
Mikrotik routeros
References
Metrics cvssV4_0

{'score': 8.8, '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'}

Subscriptions

Mikrotik Routeros
cve-icon MITRE

Status: PUBLISHED

Assigner: CERT-PL

Published:

Updated: 2026-09-05T20:39:44.166Z

Reserved: 2026-07-29T11:59:30.538Z

Link: CVE-2026-67277

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-05T20:17:18.120

Modified: 2026-09-05T21:16:50.393

Link: CVE-2026-67277

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-05T21:30:17Z

Weaknesses
  • CWE-306

    Missing Authentication for Critical Function