MikroTik RouterOS Stack-Based Buffer Overflow Vulnerability
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…
Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.
Exploitation probability EPSS · FIRST
Exploitation signals 4 / 5
- KEV catalog (CISA)08 Sept 2022
- Exploited in EUVD (ENISA)08 Sept 2022
- Used by ransomwareno
- EPSS above 10 %65.8%
- No account, over the networkyes
What to do
Fix
Apply the vendor’s fix as soon as it is available.
CISA guidance: Apply updates per vendor instructions.
Meanwhile
Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.
Manufacturers (CRA)
Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained
Description ENISA EUVD
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.
Affected products
Open source packages OSV
Affected libraries according to OSV, with fixed versions.
Timeline
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Published
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Exploitation reported (ENISA)
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Added to the KEV catalog
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CISA remediation due date
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EPSS peak: 65.8%
References
Other exploited vulnerabilities from the same vendor
- CVE-2026-67279Mikrotik RouterOS Improper Enforcement of Behavioral Workflow Vulnerability4.6 · Actively exploited
- CVE-2026-86060MikroTik RouterOS Improper Neutralization of Argument Delimiters in a Command Vulnerability5.7 · Actively exploited
- CVE-2026-67277MikroTik RouterOS Missing Authentication for Critical Function Vulnerability5.4 · Actively exploited
- CVE-2026-67276MikroTik RouterOS5.1 · Actively exploited
- CVE-2018-14847MikroTik Router OS Directory Traversal Vulnerability8.9 · Background exploitation