Description
Mikrotik RouterOS (x86) 6.40.5 through 6.49.10 (fixed in 7) allows a remote attacker to cause a denial of service (device crash) via crafted packet data to the SMB service on TCP port 445.
Published: 2026-05-08
Score: 7.5 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

A remote attacker can send specially crafted SMB packets that trigger a denial of service (CWE-400) in the RouterOS SMB service, causing it to crash and denying service. The crash renders the router unavailable, disrupting network connectivity and any services that depend on it.

Affected Systems

Devices running Mikrotik RouterOS x86 versions 6.40.5 through 6.49.10 are vulnerable. The flaw was addressed in the 7.x release line.

Risk and Exploitability

The vulnerability is exposed over the network via TCP port 445, so remote attackers can trigger it from outside the local network. The CVSS score of 7.5 indicates a significant severity, while the EPSS score of < 1% suggests a low likelihood of exploitation and there is no KEV listing. The exploit requires no special privileges; an attacker simply transmits malformed SMB traffic to force a crash.

Generated by OpenCVE AI on May 8, 2026 at 22:36 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Upgrade the router to Mikrotik RouterOS 7, which contains the fix for the SMB crash issue.
  • If an upgrade cannot be performed immediately, block inbound traffic to TCP port 445 from external networks while maintaining access from trusted internal hosts.
  • Continuously monitor router logs for abnormal SMB activity and apply the patch as soon as the upgrade is possible.

Generated by OpenCVE AI on May 8, 2026 at 22:36 UTC.

Tracking

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Advisories

No advisories yet.

History

Mon, 11 May 2026 17:00:00 +0000

Type Values Removed Values Added
First Time appeared Mikrotik
Mikrotik routeros
Vendors & Products Mikrotik
Mikrotik routeros

Fri, 08 May 2026 23:00:00 +0000

Type Values Removed Values Added
Title RouterOS SMB Service Denial of Service Vulnerability

Fri, 08 May 2026 21:00:00 +0000

Type Values Removed Values Added
Title SMB Service Denial of Service in Mikrotik RouterOS
Weaknesses CWE-120

Fri, 08 May 2026 14:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-400
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Fri, 08 May 2026 06:45:00 +0000

Type Values Removed Values Added
Title SMB Service Denial of Service in Mikrotik RouterOS
Weaknesses CWE-120

Fri, 08 May 2026 05:45:00 +0000

Type Values Removed Values Added
Description Mikrotik RouterOS (x86) 6.40.5 through 6.49.10 (fixed in 7) allows a remote attacker to cause a denial of service (device crash) via crafted packet data to the SMB service on TCP port 445.
References

Subscriptions

Mikrotik Routeros
cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2026-05-08T14:00:45.540Z

Reserved: 2024-02-26T00:00:00.000Z

Link: CVE-2024-27686

cve-icon Vulnrichment

Updated: 2026-05-08T14:00:41.769Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-05-08T06:16:09.003

Modified: 2026-05-08T16:02:14.343

Link: CVE-2024-27686

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-11T16:11:49Z

Weaknesses