CVE-2026-33825
Microsoft Defender Insufficient Granularity of Access Control Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 6 May 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
Insufficient granularity of access control in Microsoft Defender allows an authorized attacker to elevate privileges locally.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 6.75% probability · 94th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Listed 22 April 2026 · due 6 May 2026 · used in ransomware campaigns
- Weakness
- CWE-1220
- Affected
- microsoft/defender antimalware platform
- Source
- secure@microsoft.com
EPSS moved from 0.4% on 24 September 2026 to 6.7% on 27 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
CISA notes
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33825 ; https://nvd.nist.gov/vuln/detail/CVE-2026-33825
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33825Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-33825US Government Resource
- https://www.huntress.com/blog/nightmare-eclipse-intrusionThird Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.