Widely deployed Samba infrastructure; critical RCE in core file-serving service.
CVE-2026-4408
Remote code execution in Samba via check password script using %u.
Is CVE-2026-4408 being exploited?
Not confirmed. CVE-2026-4408 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 2.5% probability of exploitation in the next 30 days.
How severe is CVE-2026-4408?
CVE-2026-4408 is rated Critical with a CVSS score of 9.0. 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-2026-4408?
Yes. A fix has been recorded for CVE-2026-4408. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-4408 affect?
CVE-2026-4408 affects Samba file servers, Samba domain controllers. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-4408?
Patch Samba when available; if not, disable the check password script.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution on Samba file servers/domain controllers via check password script with %u; arbitrary commands.
Immediate action required