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major vulnerability· requires attention

RCE in Windows Active Directory; core infrastructure used across industries; could disrupt domains.

Infrastructure

CVE-2026-33826

8.0
High
EPSS 0.53%Patch availableApr 15, 2026

RCE in Windows Active Directory via adjacent network due to input validation flaw.

common questions

Is CVE-2026-33826 being exploited?

Not confirmed. CVE-2026-33826 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 0.53% probability of exploitation in the next 30 days.

How severe is CVE-2026-33826?

CVE-2026-33826 is rated High with a CVSS score of 8.0. 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-2026-33826?

Yes. A fix has been recorded for CVE-2026-33826. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2026-33826 affect?

CVE-2026-33826 affects Windows Server Active Directory, Domain controllers, AD-related services. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

What should I do about CVE-2026-33826?

Patch Windows AD; apply vendor security updates.

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

executive summary
technical analysis
affected
Windows Server Active DirectoryDomain controllersAD-related services
impact

Authenticated attacker can execute arbitrary code on domain-joined hosts across the network.

action required

Immediate action required

affected versions
Microsoft Windows Server 2012 R2
  • affected>= 6.3.9600.0 and < 6.3.9600.23132
Microsoft Windows Server 2012 R2 (Server Core installation)
  • affected>= 6.3.9600.0 and < 6.3.9600.23132
Microsoft Windows Server 2016
  • affected>= 10.0.14393.0 and < 10.0.14393.9060
Microsoft Windows Server 2016 (Server Core installation)
  • affected>= 10.0.14393.0 and < 10.0.14393.9060
Microsoft Windows Server 2019
  • affected>= 10.0.17763.0 and < 10.0.17763.8644
Microsoft Windows Server 2019 (Server Core installation)
  • affected>= 10.0.17763.0 and < 10.0.17763.8644
Microsoft Windows Server 2022
  • affected>= 10.0.20348.0 and < 10.0.20348.5020
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation)
  • affected>= 10.0.25398.0 and < 10.0.25398.2274
Microsoft Windows Server 2025
  • affected>= 10.0.26100.0 and < 10.0.26100.32690
Microsoft Windows Server 2025 (Server Core installation)
  • affected>= 10.0.26100.0 and < 10.0.26100.32690

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.

how to fix
Remediation steps are tailored for users whose stack is affected. Add this technology to your stack to see the fix checklist.
references
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