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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 29 Sep 2022.
RouterosOperating system · Mikrotik

CVE-2018-7445

CRITICAL · 9.8 CVSS v3.1 Published 2018-03-19
Fix available
A fix is available. Upgrade to 6.41.3 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild High EPSS Public exploit Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A buffer overflow was found in the MikroTik RouterOS SMB service when processing NetBIOS session request messages. Remote attackers with access to the service can exploit this vulnerability and gain code execution on the system. The overflow occurs before authentication takes place, so it is possible for an unauthenticated remote attacker to exploit it. All architectures and all devices running RouterOS before versions 6.41.3/6.42rc27 are vulnerable.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A pre-authentication buffer overflow vulnerability exists in the MikroTik RouterOS SMB service when processing NetBIOS session request messages. The overflow occurs in the NetBIOS session handling code before authentication takes place, allowing unauthenticated remote attackers to execute arbitrary code by sending specially crafted SMB NetBIOS session request packets.

MitigationUpgrade MikroTik RouterOS to version 6.41.3 or later (or 6.42rc27+ for release candidate track). If immediate upgrade is not feasible, disable or restrict the SMB service (ports 445/139) from untrusted network access using firewall rules.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
RouterosOperating system
Affected:< 6.41.3= 6.42

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify SMB service is enabled
    On the MikroTik device, access Winbox or SSH and run: /ip smb print. Alternatively, check via webfig at IP > SMB. Look for the 'enabled' parameter or check if the SMB service is listed as active.
    Affected if SMB service is enabled and the RouterOS version is in the vulnerable range (< 6.41.3 or = 6.42)
  2. Check RouterOS version
    Run the command /system resource print in Winbox terminal, SSH, or via API. This displays the installed RouterOS version under the 'version' and 'board' fields.
    Affected if The version displayed is lower than 6.41.3, or exactly equals 6.42 (for example, 6.40.9, 6.41, 6.41.1, 6.41.2, or 6.42)
  3. Confirm SMB is exposed to untrusted networks
    Review firewall rules at /ip firewall filter print and NAT rules at /ip firewall nat print. Check if the SMB service (TCP port 445) is permitted from WAN or untrusted interface sources.
    Affected if SMB is accessible from any interface other than trusted LAN segments and the version is vulnerable

If SMB is enabled on a MikroTik device running RouterOS version < 6.41.3 or exactly 6.42, and the service is reachable from untrusted networks, the device is affected by CVE-2018-7445.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 6.41.3 or later
Fixed in 6.41.3
Interim mitigation

Upgrade MikroTik RouterOS to version 6.41.3 or later (or 6.42rc27+ for release candidate track). If immediate upgrade is not feasible, disable or restrict the SMB service (ports 445/139) from untrusted network access using firewall rules.

Recommended fix High confidence

RouterOS 6.41.3 or later stable release (6.42.x and later are not affected)

  1. Backup the current RouterOS configuration before upgrading
  2. Download RouterOS version 6.41.3 or later (such as 6.43.x or 6.44.x stable) from the MikroTik download page
  3. Access the RouterOS web interface or WinBox, navigate to Files section and upload the new .npk firmware file
  4. In RouterOS, go to System > RouterBOARD > Packages and click Download & Install, OR use the /system package install command
  5. Allow the router to reboot and complete the upgrade process
  6. After reboot, verify the new version is installed using /system resource print or /system routerboard print
Caveat RouterOS upgrades may introduce configuration or feature changes; review release notes before upgrading and test in a non-production environment first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Routeros Exploited in the wild — priority engagement
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-7445 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data