Microsoft Windows EFS is widely deployed; authenticated remote code execution in core OS crypto subsystem risks broad system compromise and enterprise impact.
CVE-2026-83759
Code injection in Windows EFS enabling remote code execution by an authenticated attacker.
Is CVE-2026-83759 being exploited?
Not confirmed. CVE-2026-83759 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.
How severe is CVE-2026-83759?
CVE-2026-83759 is rated High with a CVSS score of 8.8. 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-2026-83759?
Yes. A fix has been recorded for CVE-2026-83759. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-83759 affect?
CVE-2026-83759 affects Microsoft Windows Encrypting File System (EFS), Affected Windows client and server versions (see MSRC advisory). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-83759?
Install Microsoft's security update immediately; restrict EFS network access and monitor endpoints.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authenticated attacker can inject code via EFS over a network, leading to remote code execution and potential full system compromise.
Immediate action required
- affected>= 10.0.14393.0 and < 10.0.14393.9612
- affected>= 10.0.17763.0 and < 10.0.17763.9376
- affected>= 10.0.19044.0 and < 10.0.19044.7807
- affected>= 10.0.19045.0 and < 10.0.19044.7807
- affected>= 10.0.22631.0 and < 10.0.22631.7652
- affected>= 10.0.22631.0 and < 10.0.22631.7652
- affected>= 10.0.26100.0 and < 10.0.26100.9711
- affected>= 10.0.26200.0 and < 10.0.26200.9711
- affected>= 10.0.28000.0 and < 10.0.28000.3231
- affected>= 10.0.26300.0 and < 10.0.26300.9711
- affected>= 10.0.14393.0 and < 10.0.14393.9612
- affected>= 10.0.14393.0 and < 10.0.14393.9612
- affected>= 10.0.17763.0 and < 10.0.17763.9376
- affected>= 10.0.17763.0 and < 10.0.17763.9376
- affected>= 10.0.20348.0 and < 10.0.20348.5761
- affected>= 10.0.26100.0 and < 10.0.26100.33650
- affected>= 10.0.26100.0 and < 10.0.26100.33650
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.