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d4 · tools · cve

CVE-2026-67277.

Severity, exploit probability and exploitation status for one vulnerability, drawn from NVD, FIRST EPSS and CISA's exploited catalogue.

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known exploited MikroTik RouterOS Missing Authentication for Critical Function Vulnerability

Vendor / product
MikroTik - RouterOS
Listed by CISA
2026-09-10
Federal fix deadline
2026-09-13 (passed)
Required action
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.

Scores

CVSS 4.0
8.8 high 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:
EPSS
0.87% estimated probability of exploitation in the next 30 days (higher than 57% of all CVEs)
Weakness class
CWE-306

ATT&CK techniques

inferred from weakness class no curated mapping exists for this CVE; these are the techniques typically seen with CWE-306 vulnerabilities

ReconnaissanceResource DevelopmentInitial AccessExecutionPersistencePrivilege EscalationStealthDefense ImpairmentCredential AccessDiscoveryLateral MovementCollectionCommand and ControlExfiltrationImpact

T1190 Exploit Public-Facing Application

Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

Inferred from CWE-306.

T1059 Command and Scripting Interpreter

Execution

Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.

Inferred from CWE-306.

See these techniques on the full ATT&CK matrix.

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
Last modified
2026-09-11
NVD status
Analyzed

References

CVSS measures how bad exploitation would be; EPSS estimates how likely exploitation is within 30 days; the CISA listing means it is already happening. Read them together: a CVSS 9.8 with EPSS 0.04% is usually less urgent than a CVSS 7.2 on the exploited list. Data: NVD, FIRST EPSS, CISA KEV; detail is cached for a week, scores for a day. ATT&CK techniques come from the CTID KEV mappings project where a curated mapping exists, otherwise they are inferred from the weakness class and labelled as such. ATT&CK is a registered trademark of The MITRE Corporation. © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation.