CVE-2026-21533
Published: February 10, 2026
Official Description
Microsoft Windows Remote Desktop Services contains an improper privilege management vulnerability that could allow an authorized attacker to elevate privileges locally.
CISA KEV Advisory
Microsoft Windows Improper Privilege Management Vulnerability
Microsoft Windows Remote Desktop Services contains an improper privilege management vulnerability that could allow an authorized attacker to elevate privileges locally.
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 high-severity vulnerability in Microsoft Windows Remote Desktop Services allows an authenticated local attacker to elevate their privileges. With a CVSS score of 7.8, it poses a significant risk, further emphasized by its inclusion in CISA's KEV catalog and an EPSS score of 0.01616, indicating confirmed exploitation and a notable likelihood of future exploitation.
This vulnerability is actively being exploited in the wild, confirming its use by attackers. The attack vector is local (AV:L) and requires low privileges (PR:L) and low attack complexity (AC:L).
Apply the latest security updates from Microsoft for Windows Remote Desktop Services. Implement principle of least privilege to limit potential attacker access.
Technical Analysis
CVE-2026-21533 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 7.8.
CISA has added CVE-2026-21533 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.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
News & Research Mentioning CVE-2026-21533
CISA has added six new vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog, based on evidence of active exploitation. CVE-2026-21510 Microsoft Windows Shell Protection Mechanism Failure Vulnerability CVE-2026-21513 Microsoft MSHTML Framework Security Feature Bypass Vulnerability CVE-2026-21514 Microsoft Office Word Reliance on Untrusted Inputs in a Security Decision Vulnerability CVE-2026-21519 Microsoft Windows Type Confusion Vulnerability CVE-2026-21525 Microsoft Windows NULL Pointer Dereference Vulnerability CVE-2026-21533 Windows Remote Desktop Services Elevation of Privilege Vulnerability These types of vulnerabilities are frequent attack vectors for malicious cyber actors and pose significant risks to the federal enterprise. Bi [xlite_meta score:53 src:CISA Alerts xlite_fp:88d5ff4976309c17f8264912552cef85549f24eb7de38b00c6011d2454de9f37]
All References (2)
Quick Facts
Known Threat Actors
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-21533 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