Vulnerability details
CVE-2026-21525
Actively exploited
Microsoft Windows 10Microsoft Windows 11Microsoft Windows Server
Windows Remote Access Connection Manager Denial of Service Vulnerability
CVSS 3.1
6.2Medium
Official description
Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 6.2Medium | 3.1 | CVEProject cvelistV5 (CNA) (microsoft) | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| Microsoft | Windows 10 Version 1607 | 10.0.14393.0 ≤ v < 10.0.14393.8868 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows 10 Version 1809 | 10.0.17763.0 ≤ v < 10.0.17763.8389 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows 10 Version 21H2 | 10.0.19044.0 ≤ v < 10.0.19044.6937 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows 10 Version 22H2 | 10.0.19045.0 ≤ v < 10.0.19045.6937 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows 11 Version 24H2 | 10.0.26100.0 ≤ v < 10.0.26100.7840 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows 11 Version 25H2 | 10.0.26200.0 ≤ v < 10.0.26200.7840 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows 11 version 22H3 | 10.0.22631.0 ≤ v < 10.0.22631.6649 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows 11 version 23H2 | 10.0.22631.0 ≤ v < 10.0.22631.6649 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows 11 version 26H1 | 10.0.28000.0 ≤ v < 10.0.28000.1575 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows 11 version 26H1 | 10.0.28000.0 ≤ v < 10.0.28000.1575 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2012 | 6.2.9200.0 ≤ v < 6.2.9200.25923 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2012 (Server Core installation) | 6.2.9200.0 ≤ v < 6.2.9200.25923 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2012 R2 | 6.3.9600.0 ≤ v < 6.3.9600.23022 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2012 R2 (Server Core installation) | 6.3.9600.0 ≤ v < 6.3.9600.23022 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2016 | 10.0.14393.0 ≤ v < 10.0.14393.8868 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2016 (Server Core installation) | 10.0.14393.0 ≤ v < 10.0.14393.8868 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2019 | 10.0.17763.0 ≤ v < 10.0.17763.8389 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2019 (Server Core installation) | 10.0.17763.0 ≤ v < 10.0.17763.8389 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2022 | 10.0.20348.0 ≤ v < 10.0.20348.4773 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2022, 23H2 Edition (Server Core installation) | 10.0.25398.0 ≤ v < 10.0.25398.2149 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2025 | 10.0.26100.0 ≤ v < 10.0.26100.32370 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2025 (Server Core installation) | 10.0.26100.0 ≤ v < 10.0.26100.32370 | CVEProject cvelistV5 (CNA) |
References and advisories
4- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21525 vendor-advisorypatch
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21525 government-resource
- https://www.vicarius.io/vsociety/posts/cve-2026-21525-detection-script-dos-vulnerability-in-windows-remote-access-connection-manager
- https://www.vicarius.io/vsociety/posts/cve-2026-21525-mitigation-script-dos-vulnerability-in-windows-remote-access-connection-manager
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Details
- Published
- 2026-02-10
- Last updated
- 2026-08-19
- State
- Published
- Assigner (CNA)
- microsoft
- Kolun priority
- 82 · Critical
CISA KEV catalog
- Date added
- 2026-02-10
- Due date
- 2026-03-03
- Used in ransomware
- Unknown
Exploit prediction (EPSS)
5.04%
Probability of exploitation in 30 days
92.3%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- No
- Exploitation
- Active
- Technical impact
- Partial
Weaknesses (CWE)
- CWE-476NULL Pointer Dereference