What’s Vulnerable › Vulnerabilities

CVE-2026-89028: MikroTik RouterOS < 7.24 Heap Corruption via SMB1 SessionSetupAndX

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-16 · updated 2026-09-24
• Weakness: CWE-122

Description

MikroTik RouterOS before 7.24 contains a heap memory corruption vulnerability in the userspace SMB daemon that allows remote attackers to corrupt adjacent heap memory by supplying a crafted uniPwdLen value in the SMB1 SessionSetupAndX handler. An attacker can send a malformed SMB1 request with a uniPwdLen field that triggers an integer underflow, causing the resulting value to be used as the copy length in a memory copy operation into a smaller heap buffer, corrupting adjacent heap memory.

Affected products

• MikroTik RouterOS: through 6.49.18; from 7.0.0 through 7.11.2

References

• https://forum.mikrotik.com/t/7-24-stable-is-released/272381
• https://www.vulncheck.com/advisories/mikrotik-routeros-heap-corruption-via-smb1-sessionsetupandx

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