CVE-2025-66678
Kernel driver flaw allows arbitrary read/write via crafted request.
Is CVE-2025-66678 being exploited?
Not confirmed. CVE-2025-66678 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 0.64% probability of exploitation in the next 30 days.
How severe is CVE-2025-66678?
CVE-2025-66678 is rated Critical with a CVSS score of 9.8. 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-2025-66678?
Not known from our data. No patch reference has been recorded for CVE-2025-66678, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.
What does CVE-2025-66678 affect?
CVE-2025-66678 affects Nil Hardware Editor Hardware Read & Write Utility v1.25.11.26 and earlier, HwRwDrv.sys (Windows). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2025-66678?
Update to fixed driver once released; restrict local access
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Local attacker can read/write kernel memory via HwRwDrv.sys, enabling privilege escalation to SYSTEM and potential full compromise.
Patch when possible