Patch tracker / CVE reference / CVE-2025-21171

CVE-2025-21171

CVE-2025-21171 is a high severity Microsoft vulnerability with a CVSS score of 8.8. Microsoft has shipped the fix: deploy the update below from the Microsoft Update Catalog, and see where this CVE sits against the rest on the patch tracker.

High

High severity Microsoft vulnerability, CVSS 8.8. Fixed by 1 Microsoft security update.

Senserva AI read on CVE-2025-21171Official patches for CVE-2025-21171Change historyAdmin questions

Risk summary

CVSS base
8.8
EPSS exploit probability
2.3%
Severity
High
Schedule normally
No exploitation observed: not in the CISA KEV catalog, EPSS 2%.
Fixed by KB5050526. Download from the Microsoft Update Catalog, or deploy via Windows Update, Intune, or WSUS.
Do this now: Deploy with your normal update cycle. This page refreshes daily; the verdict changes the day the data does.

Updated July 24, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.

Senserva AI Opinion for CVE-2025-21171

A remote code execution flaw in .NET whose affected list is PowerShell 7.5 across Windows, Linux, and macOS, rated High Severity at CVSS 8.8 with a 2 percent exploit probability. PowerShell runs with meaningful privileges on the systems that manage everything else, so code execution through its runtime is a lever over your automation layer. The three-platform spread means Linux management nodes need the update as much as Windows admin boxes.

Do this: Update PowerShell 7.5 on every platform it is installed, prioritizing CI agents and administrative servers.

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

Senserva AI Opinion and rich prompt for CVE-2025-21171

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

Full tracking and change history for CVE-2025-21171

Published
2025-01-14
Last revised
2025-01-29
Changes tracked
1

Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.

Exploitation and severity

Not in the CISA KEV catalog. EPSS exploit probability 2.3%. CVSS 8.8 (High).

This CVE is among the lower half of tracked Microsoft CVEs by EPSS exploit probability.

Official patch(es) for CVE-2025-21171

Moderate priority: schedule it in your normal patch cycle. In Intune or Defender, confirm whether the fixing update KB5050526 are installed across the affected products. Senserva does this automatically across your tenant and flags every missing patch.

Apply the Microsoft security update below to fix CVE-2025-21171. 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.

KB5050526

Affected products

Common questions about CVE-2025-21171

Is CVE-2025-21171 actively exploited?

It is not currently listed in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score puts the probability of exploitation in the next 30 days at 2.3%.

What patch fixes CVE-2025-21171?

Microsoft fixed CVE-2025-21171 in KB5050526. Download from the Microsoft Update Catalog, or let Intune, Windows Update, or WSUS deliver it.

Which products are affected by CVE-2025-21171?

PowerShell 7.5 installed on Linux, PowerShell 7.5 installed on MacOS, PowerShell 7.5 installed on Windows.

Can I ask my own AI about CVE-2025-21171?

Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2025-21171's key facts: severity, CVSS, EPSS exploit probability, CISA KEV status, and the fixing KB. Copy it into Claude, ChatGPT, or Copilot for a triage plan; the data is refreshed three times a day (5 AM, 12:30 PM, and 7 PM US Central).

Fixed by the same update

If you are patching CVE-2025-21171, the same update also fixes these:

CVE-2025-21176CVE-2025-21172CVE-2025-21173

Authoritative references

Official CVE record (cve.org)NVD detailMicrosoft MSRCFIRST.org EPSS

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Lexicon: the terms on this page
CVE
Common Vulnerabilities and Exposures. A unique ID for one publicly known vulnerability, such as CVE-2025-1234.
KB
Microsoft Knowledge Base article. The identifier for a specific Microsoft update.
KEV
CISA Known Exploited Vulnerabilities. CVEs confirmed exploited in the wild. Fix these first.
CVSS
Common Vulnerability Scoring System. A standardized Severity score from 0 to 10.
EPSS
Exploit Prediction Scoring System. The probability a CVE will be exploited in the next 30 days.
MSRC
Microsoft Security Response Center. Microsoft's Patch Tuesday advisories and KB-to-CVE mapping.
NVD
National Vulnerability Database (NIST). Authoritative CVE metadata and CVSS scores.
Ransomware
The vulnerability is linked to known ransomware activity.
Reference: Microsoft CVE and vulnerability management, the full CVE-to-patch lookup ranked by real-world risk, and the Microsoft patching guide, how Intune, Windows Autopatch, Defender, and Azure Update Manager fit together.
Data notice: this page, the feeds, and the API are provided as is, for informational purposes only, without warranty of any kind. Senserva, LLC does not guarantee the accuracy, completeness, or timeliness of third-party data (MSRC, NVD, CISA KEV, EPSS) and accepts no liability for actions taken based on it; verify against the authoritative vendor advisory before acting. Built daily with Senserva Trustworthy AI. All use of this data is subject to the Senserva EULA.