CVE-2025-33073
Published: October 20, 2025
Official Description
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.
CISA KEV Advisory
Microsoft Windows SMB Client Improper Access Control Vulnerability
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.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Risk Analysis
This improper access control vulnerability in Microsoft Windows SMB Client could lead to privilege escalation. An attacker could craft a malicious script to coerce a victim machine to connect and authenticate to an attacker-controlled SMB system. With an EPSS score of 0.51186, there is a high likelihood of exploitation, and its presence in CISA's KEV catalog confirms active exploitation.
This vulnerability is actively exploited in the wild and is included in CISA's Known Exploited Vulnerabilities catalog. Exploitation involves coercing a victim machine to connect to a malicious SMB server.
Administrators should apply the latest security updates for Microsoft Windows. Implement strong authentication policies and restrict outbound SMB connections to trusted destinations.
Technical Analysis
CVE-2025-33073 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2025-33073 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Affected Vendors & Products
Exploit & PoC Resources
All References (2)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2025-33073 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1