Microsoft Defender's Link Following Flaw Enables an Authorized Attacker to Elevate Privileges Locally; CISA's June 3rd KEV Deadline Has Passed

Last refreshed2026-09-27

Status: KEV | Advisory ID: CVE-2026-41091

Key Details

CVE	CVE-2026-41091
Vulnerability Name	Microsoft Defender Link Following Vulnerability
Affected products	Microsoft Defender
Exploitation status	Listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, indicating confirmed active exploitation.
Classified as	CWE-59 (Improper Link Resolution Before File Access ('Link Following'))
KEV listing	Added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2026-05-20.
Exploitation prediction (EPSS)	0.44% probability of exploitation in the next 30 days (36% percentile) -- FIRST.org's EPSS model.
Federal remediation deadline	2026-06-03 (CISA KEV, Binding Operational Directive).

Affected Products, Subsystems & Sectors

Vendor	Product	Affected Versions	Patch Status
Microsoft	Defender

Vendor

Product

Affected Versions

Patch Status

Microsoft

Defender

Subsystems	EWS Engineering Software
Sectors	Multiple

What to Know

Microsoft Defender contains a link following vulnerability that allows an authorized attacker to elevate privileges locally.

What to Do

Monitor Microsoft's web page for any future patch releases.

References

Source	Reference
NVD	https://nvd.nist.gov/vuln/detail/CVE-2026-41091
CVE	https://www.cve.org/CVERecord?id=CVE-2026-41091

Source

Reference

NVD

https://nvd.nist.gov/vuln/detail/CVE-2026-41091

CVE

https://www.cve.org/CVERecord?id=CVE-2026-41091

KEV Required Action

Field	Value
KEV Link	https://www.cisa.gov/known-exploited-vulnerabilities-catalog
Date Added to KEV	2026-05-20
Required Action Due Date	2026-06-03
Required Action	Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Field

Value

KEV Link

https://www.cisa.gov/known-exploited-vulnerabilities-catalog

Date Added to KEV

2026-05-20

Required Action Due Date

2026-06-03

Required Action

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.