# CVE-2026-21525: Windows Remote Access Connection Manager Denial of Service Vulnerability

> CVE-2026-21525: Windows Remote Access Connection Manager Denial of Service Vulnerability. CVSS 6.2 (CVSS 3.1), in CISA KEV.

Canonical: https://rewindex.com/cve/CVE-2026-21525
Last updated: 2026-08-19T16:26:04Z

- Published: 2026-02-10 17:51 UTC · Updated: 2026-08-19 16:26 UTC · Assigner: microsoft
- CVSS: 6.2 (CVSS 3.1) · Severity: Medium · Vector: 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
- EPSS: 4.8%, 92th percentile (scored 2026-10-25)
- CISA KEV: yes, added 2026-02-10, federal due date 2026-03-03, ransomware use: Unknown
- CWE: CWE-476

## Description

Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally.

## CISA 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.

## Affected vendors and products

- Microsoft: Windows 10 Version 1607
- Microsoft: Windows 10 Version 1809
- Microsoft: Windows 10 Version 21H2
- Microsoft: Windows 10 Version 22H2
- Microsoft: Windows 11 version 22H3
- Microsoft: Windows 11 Version 23H2
- Microsoft: Windows 11 Version 24H2
- Microsoft: Windows 11 Version 25H2
- Microsoft: Windows 11 version 26H1
- Microsoft: Windows 11 Version 26H1
- Microsoft: Windows Server 2012
- Microsoft: Windows Server 2012 R2
- Microsoft: Windows Server 2012 R2 (Server Core installation)
- Microsoft: Windows Server 2012 (Server Core installation)
- Microsoft: Windows Server 2016
- Microsoft: Windows Server 2016 (Server Core installation)
- Microsoft: Windows Server 2019
- Microsoft: Windows Server 2019 (Server Core installation)
- Microsoft: Windows Server 2022
- Microsoft: Windows Server 2022, 23H2 Edition (Server Core installation)
- Microsoft: Windows Server 2025
- Microsoft: Windows Server 2025 (Server Core installation)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-21525)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-21525)
- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21525](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21525)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-21525 · Markdown: https://rewindex.com/cve/CVE-2026-21525.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-21525 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:17:11.561Z