RCE in Microsoft Windows DNS affects widely deployed Windows DNS service; high-impact on enterprise infrastructure, merits broad IT distribution.
CVE-2026-62817
Out-of-bounds write in Windows DNS enabling remote code execution from adjacent networks.
Is CVE-2026-62817 being exploited?
Not confirmed. CVE-2026-62817 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 0.67% probability of exploitation in the next 30 days.
How severe is CVE-2026-62817?
CVE-2026-62817 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-2026-62817?
Yes. A fix has been recorded for CVE-2026-62817. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-62817 affect?
CVE-2026-62817 affects Microsoft Windows DNS service, Windows Server DNS component (supported versions). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-62817?
Isolate DNS servers, restrict DNS traffic, enable logging/monitoring, apply vendor patch when released.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution via OOB write in Windows DNS from adjacent network; attackers can run arbitrary code and disrupt/compromise DNS servers.
Immediate action required
- affected>= 10.0.17763.0 and < 10.0.17763.9121
- affected>= 10.0.17763.0 and < 10.0.17763.9121
- affected>= 10.0.20348.0 and < 10.0.20348.5499
- affected>= 10.0.26100.0 and < 10.0.26100.33296
- affected>= 10.0.26100.0 and < 10.0.26100.33296
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.