CVE-2026-89028 MikroTik RouterOS < 7.24 Heap Corruption via SMB1 SessionSetupAndX
Remote attackers can corrupt heap memory in MikroTik RouterOS via crafted SMB1 requests, potentially leading to code execution or service disruption.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-89028?
CVE-2026-89028 is a high-severity memory corruption vulnerability in MikroTik RouterOS, published on 16 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-89028?
How do I fix CVE-2026-89028?
No fix has been published for CVE-2026-89028 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-89028 being exploited?
There is no known exploitation of CVE-2026-89028 in the wild and no public exploit code.
Sources
Also known as GHSA-2jvh-jvq5-35jq.