CVE-2026-67277

CVE Enrichment

CVSS: 8.8 HIGH
EPSS: 1.56%
EPSS Percentile: 74.60%
CISA KEV: YES — Known Exploited Vulnerability

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)

Technical Details

CVSS Version: 4.0
CNA / NVD Source: cvd@cert.pl
Published: 06-Sep-2026 03:17
Last Modified: 11-Sep-2026 19:52
EPSS Date: 2026-10-13
CWE: CWE-306

CVSS 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 /
                            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

CISA KEV Details

Date Added: 2026-09-10
Remediation Due: 2026-09-13
Known Ransomware Campaign Use: Unknown
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.
Notes: https://mikrotik.com/supportsec/september-2026-vulnerability/ ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-67277

Affected Products / Versions

mikrotik / routeros
Version / affected range: * · from (inclusive) 6.0 · before (exclusive) 6.49.21
cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*
mikrotik / routeros
Version / affected range: * · from (inclusive) 7.0 · before (exclusive) 7.23.4
cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*
mikrotik / routeros
Version / affected range: * · from (inclusive) 7.24 · before (exclusive) 7.24.2
cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*

References

Last enrichment sync: 14-Oct-2026 07:27
Sources: NVD · FIRST EPSS · CISA KEV
Latest successful provider update; providers refresh independently.

Reported Context (1)

CVE-2026-67277 Recorded Future Reports 94 High-Impact Vulnerabilities in September 2026, Including 80 Actively Exploited

CVE (76)

Malware (6)

Threat Actors (8)

Vendors (10)

Products (67)

Tools (7)

Industries (1)

Countries (2)

Note: Related entities, including threat actors, malware, CVEs, MITRE ATT&CK techniques, vendors, products, tools, countries, and industries, are shown when they appear in the same reporting. Their presence does not necessarily mean they were targeted, compromised, vulnerable, responsible for the activity, or directly involved in the incident.