CVE-2026-89028

MikroTik RouterOS < 7.24 Heap Corruption via SMB1 SessionSetupAndX

HIGH
7.5
CVSS Score
Published: September 16, 2026 at 01:12 PM UTC
Updated: October 1, 2026 at 03:21 PM UTC
1 product affected across 1 vendorRouterOS

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Severity
HIGH7.5
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v ≤ 6.49.187.0.0 ≤ v ≤ 7.11.27.0.0
Vendor states this is fixed in 7.24.0 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-122CWE-191

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