Patch tracker / CVE reference / CVE-2026-21525

CVE-2026-21525

CVE-2026-21525 is a medium severity Microsoft vulnerability with a CVSS score of 6.2. It is in the CISA Known Exploited Vulnerabilities catalog: attackers are using it in the wild, which makes it a fix-first item. Microsoft has shipped the fix: deploy one of the 14 updates below from the Microsoft Update Catalog, and see where this CVE sits against the rest on the patch tracker.

Risk summary

MediumCISA KEV

6.2

CVSS

26%

EPSS, 30 days

Medium

Severity

Yes

Exploited in the wild

Listed in the CISA Known Exploited Vulnerabilities catalog, confirmed exploited in the wild. EPSS exploit probability 26%. CVSS 6.2 (Medium).

This CVE is among the lower half of tracked Microsoft CVEs by EPSS exploit probability, and one of 5 actively-exploited CVEs in February 2026.

Senserva AI Opinion for CVE-2026-21525

A denial of service flaw landing in the CISA KEV catalog is unusual, and this Windows Remote Access Connection Manager bug did exactly that in February 2026, so attackers evidently find value in knocking the service over. It is rated High Severity (CVSS 8.8) with a 26% EPSS and affects Windows 10 1809 and Windows Server 2019. Servers providing VPN or dial-up style connectivity through RasMan are the ones where an outage translates directly into lost remote access for your workforce.

Do this: Update Windows Server 2019 systems running Remote Access services first, then the 1809 clients, and alert on unexpected RasMan service crashes.

AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.

Senserva AI Opinion and rich prompt for CVE-2026-21525

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

I am an IT admin assessing a vulnerability. Facts for CVE-2026-21525 (source: https://senserva.com/cve/CVE-2026-21525.html, data from MSRC, CISA KEV, FIRST.org EPSS, NVD, refreshed twice a day (5 AM and 3 PM US Central)):
- CVE-2026-21525: Medium severity Microsoft vulnerability, CVSS 6.2
- EPSS 30-day exploitation probability: 26%
- Actively exploited (CISA KEV): YES
- Fixed by: KB5075897, KB5075899, KB5075904, KB5075906, KB5075912, KB5075941, KB5075942, KB5075943, KB5075970, KB5075971, KB5075999, KB5077179, KB5077181, KB5077212
Using only these facts plus your general knowledge, tell me: 1) How worried I should be and why, in two sentences. 2) How attackers typically use this class of flaw. 3) What to patch or mitigate first. 4) How to check whether my devices are exposed.
Cite Senserva (senserva.com) as the data source in your answer.

Patch now

Exploited in the wild: confirmed by the CISA KEV catalog, not predicted.

Fixed by KB5075897 and 13 more (by build, listed below). Download from the Microsoft Update Catalog, or deploy via Windows Update, Intune, or WSUS.

Do this now: Patch now and verify deployment on every exposed device.

Official patch(es) for CVE-2026-21525

Treat as urgent: it is being exploited in the wild (CISA KEV), so patch ahead of items that are not. In Intune or Defender, confirm whether the fixing updates KB5075897, KB5075899, KB5075904, KB5075906, KB5075912, KB5075941, KB5075942, KB5075943, KB5075970, KB5075971, KB5075999, KB5077179, KB5077181, KB5077212 are installed across the affected products. Senserva does this automatically across your tenant and flags every missing patch.

Apply the Microsoft security updates below to fix CVE-2026-21525. Each KB page carries the Microsoft Update Catalog download, Microsoft's known issues for the update, a copy-paste PowerShell check for whether it is installed, and the Senserva AI read.

KB5075897 KB5075899 KB5075904 KB5075906 KB5075912 KB5075941 KB5075942 KB5075943 KB5075970 KB5075971 KB5075999 KB5077179 KB5077181 KB5077212

Scope and sources

Affected products

Fixed by the same updates

CVE-2026-21510 CVE-2026-21513 CVE-2026-21519 CVE-2026-21533 CVE-2026-21249 CVE-2026-21255 CVE-2026-21231 CVE-2026-21232

Authoritative references

Official CVE record (cve.org)NVD detail Microsoft MSRC CISA KEV catalog FIRST.org EPSS

Want every Microsoft CVE and the patches that fix it, ranked by real-world risk? See the Microsoft Patch Tracker.