CVE-2026-89028CWE-122CWE-191

CVE-2026-89028

High · published September 16, 2026

CVSS v3.1
7.5
EPSS
1%
Percentile
47.0
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
8.2 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
EPSS
0.00582 · 47.0th percentile
Weaknesses
CWE-122 · Heap-based Buffer Overflow; CWE-191 · Integer Underflow (Wrap or Wraparound)
Published
2026-09-16T18:17Z
References (2)
https://forum.mikrotik.com/t/7-24-stable-is-released/272381 · [email protected]https://www.vulncheck.com/advisories/mikrotik-routeros-heap-corruption-via-smb1-sessionsetupandx · [email protected]
EPSS history
Timeline
  • 18 SEP 04:02Z
    EPSS moved — → 1%
    epss
  • 16 SEP 13:12Z
    MikroTik RouterOS < 7.24 Heap Corruption via SMB1 SessionSetupAndX
    cvelistv5