Exploited CVEs / Microsoft / CVE-2026-41091

CVE-2026-41091

Microsoft Defender Link Following Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted. Federal agencies were required to remediate by 2026-06-03 (that deadline has passed); treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Microsoft Security Update Guide (MSRC), linked below.

UnratedCISA KEV

Actively exploited Microsoft Defender vulnerability. Added to the CISA KEV catalog 2026-05-20.

Senserva AI read on CVE-2026-41091CISA required actionOfficial fix for CVE-2026-41091Admin questions

Risk summary

CVSS base
-
EPSS exploit probability
Not scored
Severity
Unrated
Added to KEV
2026-05-20
CISA due date
2026-06-03 (past due)
Patch now
Exploited in the wild: confirmed by the CISA KEV catalog, not predicted.
The fix ships from the vendor: Microsoft Security Update Guide (MSRC).
Do this now: Federal remediation deadline 2026-06-03; treat it as your outer bound. Patch now and verify deployment on every exposed device.

Updated July 25, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.

Senserva AI Opinion for CVE-2026-41091

The security tool itself is the vulnerable surface: Microsoft's Malware Protection Engine, the core of Defender, has an elevation of privilege flaw at CVSS 7.8, exploited in the wild and KEV-listed on 2026-05-20. Defender engine updates normally flow automatically, so real exposure concentrates on machines whose updates are broken or blocked.

Do this: Verify the Defender engine version is current across the fleet and fix any endpoints whose definition updates are failing.

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

Senserva AI Opinion and rich prompt for CVE-2026-41091

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

Full tracking and change history for CVE-2026-41091

Published
2026-05-19
Last revised
2026-05-26
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.

CISA required action

Federal (BOD 22-01) remediation due date: 2026-06-03 (past due).

Official fix for CVE-2026-41091

The authoritative fix and affected-version list are published by the vendor. Find the Defender advisory on Microsoft Security Update Guide (MSRC).

Common questions about CVE-2026-41091

Is CVE-2026-41091 actively exploited?

Yes. CVE-2026-41091 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2026-05-20, which means exploitation in the wild has been confirmed, not predicted.

What is the CISA deadline and required action for CVE-2026-41091?

CISA set the federal (BOD 22-01) remediation due date at 2026-06-03, which has passed; treat any unremediated system as overdue.

What fixes CVE-2026-41091?

The authoritative fix is in the vendor advisory: see Microsoft Security Update Guide (MSRC) for the patched Defender versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.

Can I ask my own AI about CVE-2026-41091?

Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2026-41091's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed twice a day (5 AM and 3 PM US Central).

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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.