Exploited vulnerabilities / CVE-2026-21533
Confirmed exploited · privilege escalation · Microsoft WindowsCVE-2026-21533
Microsoft Windows privilege escalation, confirmed exploited in the wild.
Microsoft Windows Remote Desktop Services contains an improper privilege management vulnerability that could allow an authorized attacker to elevate privileges locally.
| CISA's name for it | Microsoft Windows Improper Privilege Management Vulnerability |
|---|---|
| Vendor and product | Microsoft · Windows |
| Type | privilege escalation · CWE-269 |
| Exploited | Confirmed by CISA listed 10 February 2026 |
| Likelihood | more likely to be exploited than most |
| Deadline | 3 March 2026 · already passed |
| Used in ransomware | Not reported |
| Advisories | msrc.microsoft.com ↗ · nvd.nist.gov ↗ |
Three steps, in this order
Install the update on every affected system, servers and workstations alike.
Escalation bugs are chained after a first foothold: check for other exposures an attacker could start from.
Review who holds administrative rights, and alert on new ones.
| CISA's 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. |
|---|
Know before someone else finds it
Threat Landscape Monitoring fingerprints the software your internet-facing hosts disclose and matches it, every day, against this list and the exploitation scores. When a new entry touches something you run, you are told once, with the host and the fix. The free plan covers one domain.
CVE-2026-21533 in short
Is CVE-2026-21533 being exploited?
Yes. CISA added CVE-2026-21533 to its Known Exploited Vulnerabilities catalogue on 10 February 2026, which it does only on evidence of exploitation in the wild.
What is the CISA deadline for CVE-2026-21533?
US federal agencies must remediate it by 3 March 2026. Everyone else should treat that date as the latest safe point to patch an internet-facing system.
How likely is CVE-2026-21533 to be exploited in the next 30 days?
FIRST's Exploit Prediction Scoring System gives it 4.3%, the 91st percentile of every CVE it scores.
How do I fix CVE-2026-21533?
Install the update on every affected system, servers and workstations alike. Escalation bugs are chained after a first foothold: check for other exposures an attacker could start from. Review who holds administrative rights, and alert on new ones.
Other Microsoft vulnerabilities being exploited
| CVE | Product | Type | Listed |
|---|---|---|---|
| CVE-2026-124194 | Office | exploited vulnerability | 10 November 2026 |
| CVE-2026-96951 | Windows | command injection | 13 October 2026 |
| CVE-2026-65660 | SharePoint | exploited vulnerability | 25 September 2026 |
| CVE-2026-81963 | Windows | privilege escalation | 8 September 2026 |
| CVE-2026-85880 | Windows | privilege escalation | 8 September 2026 |
| CVE-2019-1068 | SQL Server | remote code execution | 26 August 2026 |
Sources: CISA Known Exploited Vulnerabilities catalogue (released 10 November 2026) and FIRST EPSS. Page compiled automatically by SAK T.L.M, the threat-intelligence tool of SAK T.E.C, on 13 November 2026.