CVEs / CVE-2025-33073
CVE-2025-33073: Microsoft Windows SMB Client Improper Access Control Vulnerability
- Known exploited in the CISA KEV catalog since 20 Oct 2025
- high 8.8 CVSS 3.1 (from the CNA)
- EPSS 82.6% chance of exploitation in the next 30 days, higher than 99% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
Microsoft Windows SMB Client contains an improper access control vulnerability that could allow for privilege escalation. An attacker could execute a specially crafted malicious script to coerce the victim machine to connect back to the attack system using SMB and authenticate.
Description
Improper access control in Windows SMB allows an authorized attacker to elevate privileges over a network.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| Microsoft Windows 10 Version 1507 | from 10.0.10240.0, before 10.0.10240.21034 | 10.0.10240.21034 |
| Microsoft Windows 10 Version 1607 | from 10.0.14393.0, before 10.0.14393.8148 | 10.0.14393.8148 |
| Microsoft Windows 10 Version 1809 | from 10.0.17763.0, before 10.0.17763.7434 | 10.0.17763.7434 |
| Microsoft Windows 10 Version 21H2 | from 10.0.19044.0, before 10.0.19044.5965 | 10.0.19044.5965 |
| Microsoft Windows 10 Version 22H2 | from 10.0.19045.0, before 10.0.19045.5965 | 10.0.19045.5965 |
| Microsoft Windows 11 version 22H2 | from 10.0.22621.0, before 10.0.22621.5472 | 10.0.22621.5472 |
| Microsoft Windows 11 version 22H3 | from 10.0.22631.0, before 10.0.22631.5472 | 10.0.22631.5472 |
| Microsoft Windows 11 Version 23H2 | from 10.0.22631.0, before 10.0.22631.5472 | 10.0.22631.5472 |
| Microsoft Windows 11 Version 24H2 | from 10.0.26100.0, before 10.0.26100.4349 | 10.0.26100.4349 |
| Microsoft Windows Server 2008 R2 Service Pack 1 | from 6.1.7601.0, before 6.1.7601.27769 | 6.1.7601.27769 |
| Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation) | from 6.1.7601.0, before 6.1.7601.27769 | 6.1.7601.27769 |
| Microsoft Windows Server 2008 Service Pack 2 | from 6.0.6003.0, before 6.0.6003.23351 | 6.0.6003.23351 |
| Microsoft Windows Server 2008 Service Pack 2 (Server Core installation) | from 6.0.6003.0, before 6.0.6003.23351 | 6.0.6003.23351 |
| Microsoft Windows Server 2012 | from 6.2.9200.0, before 6.2.9200.25522 | 6.2.9200.25522 |
| Microsoft Windows Server 2012 (Server Core installation) | from 6.2.9200.0, before 6.2.9200.25522 | 6.2.9200.25522 |
| Microsoft Windows Server 2012 R2 | from 6.3.9600.0, before 6.3.9600.22620 | 6.3.9600.22620 |
| Microsoft Windows Server 2012 R2 (Server Core installation) | from 6.3.9600.0, before 6.3.9600.22620 | 6.3.9600.22620 |
| Microsoft Windows Server 2016 | from 10.0.14393.0, before 10.0.14393.8148 | 10.0.14393.8148 |
| Microsoft Windows Server 2016 (Server Core installation) | from 10.0.14393.0, before 10.0.14393.8148 | 10.0.14393.8148 |
| Microsoft Windows Server 2019 | from 10.0.17763.0, before 10.0.17763.7434 | 10.0.17763.7434 |
| Microsoft Windows Server 2019 (Server Core installation) | from 10.0.17763.0, before 10.0.17763.7434 | 10.0.17763.7434 |
| Microsoft Windows Server 2022 | from 10.0.20348.0, before 10.0.20348.3807 | 10.0.20348.3807 |
| Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) | from 10.0.25398.0, before 10.0.25398.1665 | 10.0.25398.1665 |
| Microsoft Windows Server 2025 | from 10.0.26100.0, before 10.0.26100.4349 | 10.0.26100.4349 |
| Microsoft Windows Server 2025 (Server Core installation) | from 10.0.26100.0, before 10.0.26100.4349 | 10.0.26100.4349 |
Exploitation
| In CISA KEV since | 20 Oct 2025 |
|---|---|
| Due date for US federal agencies | 10 Nov 2025 |
| Used in ransomware campaigns | Unknown |
| Required action | Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. |
Severity
| CVSS 3.1 | 8.8 highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HScored by the CNA ([email protected]) |
|---|---|
| Weakness | CWE-284 |
References
- CVE-2025-33073 on NVD
- CVE-2025-33073 in the CISA KEV catalog
- https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2025-33073 (cited by CISA)
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-33073 Vendor Advisory
- https://www.vicarius.io/vsociety/posts/cve-2025-33073-detection-script-improper-access-control-in-windows-smb-affects-microsoft-products Third Party Advisory
- https://www.vicarius.io/vsociety/posts/cve-2025-33073-mitigation-script-improper-access-control-in-windows-smb-affects-microsoft-products Mitigation, Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-33073 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.