CVE-2026-67277

Awaiting Analysis
Published: 05 Sept 2026, 20:00
Last modified:11 Sept 2026, 03:55

Vulnerability Summary

Overall Risk (default)
medium
45/100
CVSS Score
8.8 HIGH
v4.0 (cve.org)
EPSS Score
0.43% LOW
0% probability 0.00%
KEV
Listed
CISA
1 listing
Ransomware
No reports
Public exploits
1 found
Dark Web
Not detected

Timeline

05 Sept 2026, 20:00
Published
Vulnerability first disclosed
10 Sept 2026, 00:00
Added to CISA KEV
MikroTik RouterOS Missing Authentication for Critical Function Vulnerability
11 Sept 2026, 03:55
Last Modified
Vulnerability information updated
13 Sept 2026, 00:00
CISA Remediation Due
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.

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)

CVSS Metrics

  • v4.0•HIGH•Score: 8.8CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N
  • v4.0•HIGH•Score: 8.8CVSS: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

EPSS Trends

Current EPSS score: 0.43%• Percentile: 37%

Techniques & Countermeasures

  • CWE-306•Missing Authentication for Critical Function

    The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

Affected Systems

  • mikrotik•routeros

    ≥ 7.24, < 7.24.2 | ≥ 7.0.0, < 7.23.4 | ≥ 6.0.0, < 6.49.21

References (8)