MikroTik RouterOS < 7.24 Heap Corruption via SMB1 SessionSetupAndX
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-122 and the CVSS impact.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA RouterOS (MikroTik) Fixed in 7.24.0
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Advisory ·
MikroTik RouterOS — Release Notes
2 records Highest priority Priority LOW 2 LOW
Other records, highest priority first
- TI-2026-40892 MikroTik RouterOS < 7.24 Out-of-Bounds Read via SMB1 SessionSetupAndXPriority LOW 34
Timeline
- 2026-10-02 Threatist record created from CVE-2026-89028
- 2026-10-03 Alias added: GHSA-2jvh-jvq5-35jq
References
Patch 1
More MikroTik vulnerabilities
- TI-2018-05369 A buffer overflow was found in the MikroTik RouterOS SMB service when processing NetBIOS… KEVCVSS 3.1CRITICAL 9.8
- TI-2026-58872 SSH session privilege manipulation via a crafted username in Mikrotik RouterOS KEVCVSS 4.0CRITICAL 9.2
- TI-2018-10669 MikroTik RouterOS through 6.42 allows unauthenticated remote attackers to read arbitrary… KEVCVSS 3.1CRITICAL 9.1
- TI-2026-47574 Kernel memory disclosure and denial of service in MikroTik RouterOS btest service KEVCVSS 4.0HIGH 8.8
- TI-2026-47576 SSH Pre-Authentication Rekey State Bypass in MikroTik RouterOS KEVCVSS 4.0MEDIUM 6.9
- TI-2022-22302 Out-of-bounds read in MicroTik RouterOS CVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-89028 · CVE Program
- CVE-2026-89028 · NVD
- FIRST EPSS
- GHSA-2jvh-jvq5-35jq · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences