Affects MikroTik RouterOS, a widely deployed network OS; network-facing SMB vulnerability can disrupt routers and services across organizations.
CVE-2026-89028
RouterOS SMB1 heap corruption via crafted SessionSetupAndX; possible RCE/DoS
Is CVE-2026-89028 being exploited?
Not confirmed. CVE-2026-89028 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.56% probability of exploitation in the next 30 days.
How severe is CVE-2026-89028?
CVE-2026-89028 is rated High with a CVSS score of 8.2. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-89028?
Yes. A fix has been recorded for CVE-2026-89028. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-89028 affect?
CVE-2026-89028 affects MikroTik RouterOS (SMB userspace daemon) versions before 7.24. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-89028?
Update to RouterOS 7.24 and block SMB (TCP 445) from untrusted networks
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote heap memory corruption via crafted SMB1 SessionSetupAndX; may enable remote code execution or cause device crashes/DoS.
Immediate action required
- affected<= 6.49.18
- affected>= 7.0.0 and <= 7.11.2
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.