CVE-2026-21525
Confirmed PUBLISHEDWindows Remote Access Connection Manager Denial of Service Vulnerability
1 day faster than CISA KEV
Recommended Action
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
At a Glance
Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally.
- CVE Published
- Feb 10, 2026
- Exploitation Reported
- Jun 01, 2026
- CVSS
- 6.2 Medium
- EPSS
- 5.0%
Affected Versions
| Vendor | Product | Version | Status |
|---|---|---|---|
| Microsoft |
Windows 10 Version 1607
|
10.0.14393.0 to < 10.0.14393.8868 |
Affected |
| Microsoft |
Windows 10 Version 1809
|
10.0.17763.0 to < 10.0.17763.8389 |
Affected |
| Microsoft |
Windows 10 Version 21H2
|
10.0.19044.0 to < 10.0.19044.6937 |
Affected |
| Microsoft |
Windows 10 Version 22H2
|
10.0.19045.0 to < 10.0.19045.6937 |
Affected |
| Microsoft |
Windows 11 version 22H3
|
10.0.22631.0 to < 10.0.22631.6649 |
Affected |
| Microsoft |
Windows 11 Version 23H2
|
10.0.22631.0 to < 10.0.22631.6649 |
Affected |
| Microsoft |
Windows 11 Version 24H2
|
10.0.26100.0 to < 10.0.26100.7840 |
Affected |
| Microsoft |
Windows 11 Version 25H2
|
10.0.26200.0 to < 10.0.26200.7840 |
Affected |
| Microsoft |
Windows 11 version 26H1
|
10.0.28000.0 to < 10.0.28000.1575 |
Affected |
| Microsoft |
Windows 11 Version 26H1
|
10.0.28000.0 to < 10.0.28000.1575 |
Affected |
| Microsoft |
Windows Server 2012
|
6.2.9200.0 to < 6.2.9200.25923 |
Affected |
| Microsoft |
Windows Server 2012 (Server Core installation)
|
6.2.9200.0 to < 6.2.9200.25923 |
Affected |
| Microsoft |
Windows Server 2012 R2
|
6.3.9600.0 to < 6.3.9600.23022 |
Affected |
| Microsoft |
Windows Server 2012 R2 (Server Core installation)
|
6.3.9600.0 to < 6.3.9600.23022 |
Affected |
| Microsoft |
Windows Server 2016
|
10.0.14393.0 to < 10.0.14393.8868 |
Affected |
| Microsoft |
Windows Server 2016 (Server Core installation)
|
10.0.14393.0 to < 10.0.14393.8868 |
Affected |
| Microsoft |
Windows Server 2019
|
10.0.17763.0 to < 10.0.17763.8389 |
Affected |
| Microsoft |
Windows Server 2019 (Server Core installation)
|
10.0.17763.0 to < 10.0.17763.8389 |
Affected |
| Microsoft |
Windows Server 2022
|
10.0.20348.0 to < 10.0.20348.4773 |
Affected |
| Microsoft |
Windows Server 2022, 23H2 Edition (Server Core installation)
|
10.0.25398.0 to < 10.0.25398.2149 |
Affected |
| Microsoft |
Windows Server 2025
|
10.0.26100.0 to < 10.0.26100.32370 |
Affected |
| Microsoft |
Windows Server 2025 (Server Core installation)
|
10.0.26100.0 to < 10.0.26100.32370 |
Affected |
CVE References
- Windows Remote Access Connection Manager Denial of Service Vulnerability msrc.microsoft.com · Vendor Advisory https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21525
Recommended Actions
- Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
- Use the Pro API to automate enrichment, telemetry, and workflow delivery for VM, SOC, and CTI pipelines.
Known Exploited Vulnerability Sources
Catalogues that list this CVE as a known exploited vulnerability.
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CVE First | 2026-06-01 10:50 UTC |
| CISA | 2026-06-02 14:03 UTC |
No detection artifacts or sensor request patterns are available for this CVE yet.
Check back as sensor telemetry and scanner integrations are updated.
Virtual Patch
Compensating WAF rules to help reduce exposure to this CVE. Rule content and deployable vendor exports are available with KEVIntel Enterprise.
KEVIntel does not currently have a virtual patch for this CVE. When available, KEVIntel virtual patches ship as deployable ModSecurity, Cloudflare, and AWS WAF rules.
Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to KEVIntel Enterprise users.
CVSS Scores
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Exploitation Status
Exploited in the wild
Recorded 2026-06-01 10:50:47 UTC · CVE
Weaknesses (CWE)
-
NULL Pointer Dereference
Timeline
Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.
-
14:03 UTC about 1 month ago14:03 UTC · about 1 month ago
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
10:50 UTC about 2 months ago10:50 UTC · about 2 months ago
Added to KEVIntel KEV Feed
High-confidence, third-party attested exploitation
-
17:51 UTC 5 months ago17:51 UTC · 5 months ago
CVE published
Vulnerability disclosed publicly
-
18:10 UTC 7 months ago18:10 UTC · 7 months ago
CVE ID reserved
Identifier reserved by the CNA
Automate This Intelligence with the Pro API
Confidence scoring, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
Pro API Example
GET /api/v2/pro/kevs/CVE-2026-21525
{
"cve_id": "CVE-2026-21525",
"title": "Windows Remote Access Connection Manager Denial of Service Vulnerability",
"affected_vendor": "Microsoft",
"affected_product": "Windows 10 Version 1607, Windows 10 Version 1809, Windows 10 Version 21H2, Windows 10 Version 22H2, Windows 11 version 22H3, Windows 11 Version 23H2, Windows 11 Version 24H2, Windows 11 Version 25H2, Windows 11 version 26H1, Windows 11 Version 26H1, Windows Server 2012, Windows Server 2012 (Server Core installation), Windows Server 2012 R2, Windows Server 2012 R2 (Server Core installation), Windows Server 2016, Windows Server 2016 (Server Core installation), Windows Server 2019, Windows Server 2019 (Server Core installation), Windows Server 2022, Windows Server 2022, 23H2 Edition (Server Core installation), Windows Server 2025, Windows Server 2025 (Server Core installation)",
"affected_versions": [
{ "vendor": "...", "product": "...", "status": "affected", "display_label": "..." }
],
"confidence": "Confirmed",
"cvss_score": 6.2,
"epss_score": 0.04956,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}