IRONSMITHINTEL
HIGHCVSS7.8
|
Actively Exploited
|CISA KEV|CVE-2026-33825|Auth: low — authenticated user|Reboot: required|Manual only

Microsoft Defender < 4.18.26030.3011

Microsoft Defender contains an insufficient granularity of access control vulnerability that could allow an authorized attacker to escalate privileges locally.

Published Apr 14, 2026 · Updated May 16, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

A local attacker, with a low-privilege account, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. Federal agencies are required to remediate by 2026-05-06 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a Software Vulnerability (CWE-1220) (CWE-1220) vulnerability in Microsoft Defender. Insufficient granularity of access control in Microsoft Defender allows an authorized attacker to elevate privileges locally. Exploitation requires local access, low attack complexity, a low-privilege authenticated account, and no user interaction required.

Am I affected?Quick check

Probably yes if any of these apply:

●IT Security
●Running defender antimalware platform: v < 4.18.26030.3011
Fixed in4.18.26030.3011
Real-world incidentsWhat we've seen

CISA added this CVE to the Known Exploited Vulnerabilities catalog on 2026-04-22 based on evidence of active exploitation in the wild. Federal agencies required to remediate by 2026-05-06.

How to patch

Manual remediation steps

Apply the Microsoft Security Update

This vulnerability is fixed by Microsoft's official security update.

Affected Products

    1
    Microsoft Defender Antimalware Platform

Installation Methods

Windows Update (recommended)

1
Open Settings → Windows Update → Check for updates
2
The security update will be offered if applicable to your system
3
Restart when prompted

Verification

Confirm the update is installed:

Get-HotFix | Sort-Object InstalledOn -Descending | Select-Object -First 10

References

    1
    Microsoft Security Response Center: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33825
    1
    NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2026-33825
    1
    CISA KEV: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-33825

Discovery Credit

Yuanpei XU (HUST) with Diffract & 0x25028335 & 0xa773900, <a href="https://github.com/steadytao">Zen Dodd</a>

PowerShell automationComing soon

No tested PowerShell script for this entry yet. We’re prioritising automation based on user demand.

References

↗ CVE-2026-33825↗ MSRC Advisory↗ NVD