Core Microsoft Windows DNS component affected; network remote privilege escalation in a ubiquitous OS can impact many organizations and warrants broad IT notice.
CVE-2026-62778
Windows DNS use-after-free allows remote privilege escalation
Is CVE-2026-62778 being exploited?
Not confirmed. CVE-2026-62778 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 0.51% probability of exploitation in the next 30 days.
How severe is CVE-2026-62778?
CVE-2026-62778 is rated High with a CVSS score of 8.1. 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-2026-62778?
Yes. A fix has been recorded for CVE-2026-62778. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-62778 affect?
CVE-2026-62778 affects Microsoft Windows DNS service (client and server DNS components). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-62778?
Apply vendor patch immediately; if unavailable, restrict DNS service access and firewall DNS traffic.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote attackers can exploit a DNS use-after-free to elevate privileges (potentially to SYSTEM) over the network.
Immediate action required
- affected>= 10.0.14393.0 and < 10.0.14393.9418
- affected>= 10.0.17763.0 and < 10.0.17763.9121
- affected>= 6.2.9200.0 and < 6.2.9200.26280
- affected>= 6.3.9600.0 and < 6.3.9600.23338
- affected>= 6.3.9600.0 and < 6.3.9600.23338
- affected>= 6.2.9200.0 and < 6.2.9200.26280
- affected>= 10.0.14393.0 and < 10.0.14393.9418
- affected>= 10.0.14393.0 and < 10.0.14393.9418
- 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.