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MikroTik RouterOS SMB1 SessionSetupAndX Handler Integer Underflow in uniPwdLen Corrupts Adjacent Heap Memory

Last refreshed2026-09-29

Status: NEW  |  Advisory ID: CVE-2026-89028

Key Details

CVECVE-2026-89028
CVSS Score / Version7.5 (High) / CVSS v3.1
Updated2026-09-24
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Proseattack vector is network; attack complexity is low; privileges required is none; user interaction is none; scope is unchanged; confidentiality impact is none; integrity impact is none; availability impact is high.
Classified asCWE-122 (Heap-based Buffer Overflow)

What to Know

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. (NVD)

References

SourceReference
NVDhttps://nvd.nist.gov/vuln/detail/CVE-2026-89028
CVEhttps://www.cve.org/CVERecord?id=CVE-2026-89028