Widely-used Windows OS kernel; remote code execution could disrupt enterprise operations.
CVE-2026-45657
Use-after-free in Windows Kernel enables remote code execution over network.
Is CVE-2026-45657 being exploited?
Not confirmed. CVE-2026-45657 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 15% probability of exploitation in the next 30 days.
How severe is CVE-2026-45657?
CVE-2026-45657 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-2026-45657?
Yes. A fix has been recorded for CVE-2026-45657. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-45657 affect?
CVE-2026-45657 affects Windows OS kernel, Windows Server family. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-45657?
Monitor; plan patch deployment when released.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution with SYSTEM privileges via network exploit.
Patch when possible
- affected>= 10.0.22631.0 and < 10.0.22631.7219
- affected>= 10.0.22631.0 and < 10.0.22631.7219
- affected>= 10.0.26100.0 and < 10.0.26100.8655
- affected>= 10.0.26200.0 and < 10.0.26200.8655
- affected>= 10.0.28000.0 and < 10.0.28000.2269
- affected>= 10.0.20348.0 and < 10.0.20348.5256
- affected>= 10.0.26100.0 and < 10.0.26100.32995
- affected>= 10.0.26100.0 and < 10.0.26100.32995
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.