CVE-2026-21525
Windows Remote Access Connection Manager Denial of Service Vulnerability
Exploited in the wild. In CISA KEV since 2026‑02‑10. A vendor fix is available.
What to do
The vendor has published a fix. Version details are below where the sources state them.
What it is
From the CVE record
Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Listed as exploited in the wild since 2026-02-10.
US federal agencies must remediate by 2026-03-03.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
4.8% chance of exploitation activity in the next 30 days, which ranks it in the 92nd percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
9 events over 135 days, from the signal feeds we watch.
- OpenVAS check added
- EPSS band changemoderate → low
- EPSS band changelow → moderate
- Patch availablerecord updated
- Added to CISA KEVpublished, weakness classified, att&ck mapped
Affected products
- Windows 10 Version 1607Operating Systems / windows
- Windows 11 version 22H3Operating Systems / windows
- Windows Server 2012 (Server Core installation)Operating Systems / windows
- Windows Server 2012 R2 (Server Core installation)Operating Systems / windows
- Windows Server 2016 (Server Core installation)Operating Systems / windows
- Windows Server 2019 (Server Core installation)Operating Systems / windows
- Windows Server 2022, 23H2 Edition (Server Core installation)Operating Systems / windows
- Windows Server 2025 (Server Core installation)Operating Systems / windows
And 48 more affected products. See all after sign-in
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Scored 6.2 by NVD.
How it is reached
- Attack Vector LocalRequires local access to the vulnerable system (e.g. local login, malicious file)
- Attack Complexity LowNo special conditions — the attack can be reliably reproduced
- Privileges Required NoneNo authentication required — anyone can exploit this
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope UnchangedImpact is limited to the vulnerable component itself
Impact if exploited
- Confidentiality NoneNo confidentiality impact
- Integrity NoneNo integrity impact
- Availability HighTotal denial of service — the component is completely unavailable
Weaknesses
ATT&CK techniques
Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.
Sources
Watch the software you run.
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We'll flag the next CVE, public exploit or patch for Windows 10 Version 1607, not every advisory. This one: actively exploited.
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