CVE-2026-21667
Authenticated domain user can trigger remote code execution on Backup Server.
Is CVE-2026-21667 being exploited?
Not confirmed. CVE-2026-21667 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 1.1% probability of exploitation in the next 30 days.
How severe is CVE-2026-21667?
CVE-2026-21667 is rated Critical with a CVSS score of 9.9. 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-2026-21667?
Yes. A fix has been recorded for CVE-2026-21667. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-21667 affect?
CVE-2026-21667 affects Backup Server. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-21667?
Patch when available; restrict domain-user privileges; monitor backups.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
RCE via authenticated domain user on Backup Server; attacker can execute code and take control.
Immediate action required