Patch tracker / CVE reference / CVE-2025-21400

CVE-2025-21400

CVE-2025-21400 is a high severity Microsoft vulnerability with a CVSS score of 8.0. Its EPSS score puts the probability of exploitation in the next 30 days at 34%. Microsoft has shipped the fix: deploy one of the 3 updates 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 8.0. Fixed by 3 Microsoft security updates.

Senserva AI read on CVE-2025-21400Official patches for CVE-2025-21400Change historyAdmin questions

Risk summary

CVSS base
8.0
EPSS exploit probability
34%
Severity
High
Patch this cycle
Not confirmed exploited yet, but the 30-day exploit probability is high (EPSS 34%).
Fixed by KB5002678 and 2 more (by build, listed below). Download from the Microsoft Update Catalog, or deploy via Windows Update, Intune, or WSUS.
Do this now: Patch in this maintenance window; do not let it slip to the next one.

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

Senserva AI Opinion for CVE-2025-21400

An authenticated remote code execution flaw in SharePoint Server 2016, 2019, and Subscription Edition, High Severity at CVSS 8.0, but with a 30 percent EPSS score that is roughly ten times higher than the other SharePoint entries on this page. Elevated EPSS on a SharePoint bug is a leading indicator worth respecting given how fast prior SharePoint exploits spread once weaponized. Any phished user account can supply the required authentication.

Do this: Patch this SharePoint CVE ahead of the lower-EPSS ones and check farm audit logs for unusual authenticated requests if patching was delayed.

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

Senserva AI Opinion and rich prompt for CVE-2025-21400

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

Full tracking and change history for CVE-2025-21400

Published
2025-02-11
Last revised
2025-02-11
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 34%. CVSS 8.0 (High).

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

Official patch(es) for CVE-2025-21400

Elevated priority: high severity or a meaningful exploitation probability, sooner if an affected product is internet-facing. In Intune or Defender, confirm whether the fixing updates KB5002678, KB5002681, KB5002685 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-2025-21400. 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.

KB5002678KB5002681KB5002685

Affected products

Common questions about CVE-2025-21400

Is CVE-2025-21400 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 34%.

What patch fixes CVE-2025-21400?

Microsoft fixed CVE-2025-21400 in KB5002678, KB5002681, KB5002685. Download from the Microsoft Update Catalog, or let Intune, Windows Update, or WSUS deliver it.

Which products are affected by CVE-2025-21400?

Microsoft SharePoint Enterprise Server 2016, Microsoft SharePoint Server 2019, Microsoft SharePoint Server Subscription Edition.

Can I ask my own AI about CVE-2025-21400?

Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2025-21400'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).

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.