Microsoft Malware Protection Engine RedSun link following

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.6$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as critical, has been found in Microsoft Malware Protection Engine. Affected is an unknown function. Performing a manipulation results in link following. This vulnerability is cataloged as CVE-2026-41091. The attack must be initiated from a local position. Furthermore, there is an exploit available.

Detailsinfo

A vulnerability classified as critical has been found in Microsoft Malware Protection Engine (affected version unknown). This affects an unknown functionality. The manipulation with an unknown input leads to a link following vulnerability. CWE is classifying the issue as CWE-59. The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Improper link resolution before file access ('link following') in Microsoft Defender allows an authorized attacker to elevate privileges locally.

The advisory is shared at msrc.microsoft.com. This vulnerability is uniquely identified as CVE-2026-41091 since 04/16/2026. The exploitability is told to be easy. An attack has to be approached locally. Technical details are unknown but an exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 05/30/2026).

It is declared as attacked. The vulnerability scanner Nessus provides a plugin with the ID 316462 (Security Update for Windows Defender (May 2026) (CVE-2026-41091)), which helps to determine the existence of the flaw in a target environment. The CISA Known Exploited Vulnerabilities Catalog lists this issue since 05/20/2026 with a due date of 06/03/2026:

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

The vulnerability is also documented in the databases at Zero-Day.cz (1099), Tenable (316462) and EUVD (EUVD-2026-31101). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

Vendor

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.8
VulDB Meta Temp Score: 7.6

VulDB Base Score: 7.8
VulDB Temp Score: 7.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.8
CNA Vector (microsoft): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Link following
CWE: CWE-59
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Attacked

EPSS Score: 🔒
EPSS Percentile: 🔒

KEV Added: 🔒
KEV Due: 🔒
KEV Remediation: 🔒
KEV Ransomware: 🔒
KEV Notice: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 316462
Nessus Name: Security Update for Windows Defender (May 2026) (CVE-2026-41091)

Zero-Day.cz: 🔒

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

04/16/2026 CVE reserved
05/20/2026 +34 days Advisory disclosed
05/20/2026 +0 days VulDB entry created
05/30/2026 +10 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-41091 (🔒)
GCVE (CVE): GCVE-0-2026-41091
GCVE (VulDB): GCVE-100-364869
EUVD: 🔒
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 05/20/2026 15:34
Updated: 05/30/2026 06:34
Changes: 05/20/2026 15:34 (61), 05/20/2026 22:14 (13), 05/21/2026 01:40 (1), 05/22/2026 20:40 (2), 05/22/2026 20:49 (2), 05/30/2026 06:34 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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