CVE-2026-67277

Published Sep 5, 2026

Last updated a day ago

Overview

AI description

Automated description summarized from trusted sources.

CVE-2026-67277 is a vulnerability affecting the bandwidth-test service within MikroTik RouterOS. This flaw allows an unauthenticated client to establish a "related" btest connection before the primary session has completed its authentication process. An attacker can leverage this state to initiate an IPv4 UDP test. When the `random-data` parameter is set to `false`, the sender transmits an uninitialized tail from a kernel packet buffer, which can lead to the leakage of kernel memory. Additionally, an unchecked, inverted packet-size interval can cause an unsigned integer underflow and anomalously large fragmented output, potentially resulting in a remote denial-of-service (DoS) attack that restarts the RouterOS kernel or crashes the device.

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)
Source: cvd@cert.pl
NVD status: Awaiting Analysis

Risk scores

CVSS 4.0

Type: Secondary
Base score: 8.8
Impact score: -
Exploitability score: -
Vector string: 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
Severity: HIGH

Weaknesses

cvd@cert.pl: CWE-306

Hype score is a measure of social media activity compared against trending CVEs from the past 12 months. Max score 100.

Hype score: 8

References