PT-2026-42157 · Microsoft · Defender

Published 2026-05-20 · Updated 2026-05-21 · CVE-2026-41091

Positive Technologies (AI Summary)

CVSS v3.1

7.8

High

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions Microsoft Defender (affected versions not specified)

Description Improper link resolution before file access, also known as link following, allows an authorized attacker to elevate privileges locally. This issue has been actively exploited in the wild as a zero-day.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

LPE

DoS

Link Following

Weakness Enumeration

CWE-59

Related Identifiers

CVE-2026-41091

Affected Products

Defender

References · 26

• https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-41091 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-41091 · Security Note
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-41091 · Vendor Advisory
• https://twitter.com/dailytechonx/status/2057419574153302464 · Twitter Post
• https://twitter.com/ThreatLevelAI/status/2057163364246122634 · Twitter Post
• https://twitter.com/TechTranslators/status/2057193245583515856 · Twitter Post
• https://t.me/thehackernews/9054 · Telegram Post
• https://twitter.com/helpnetsecurity/status/2057417181592277256 · Twitter Post
• https://twitter.com/nims213/status/2057400307164844464 · Twitter Post
• https://twitter.com/TweetThreatNews/status/2057423687045775506 · Twitter Post
• https://twitter.com/threadlinqs/status/2057385538361979067 · Twitter Post
• https://twitter.com/TweetThreatNews/status/2057431244174934259 · Twitter Post
• https://cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-41091 · Note
• https://twitter.com/shah_sheikh/status/2057416429100728387 · Twitter Post
• https://twitter.com/threadlinqs/status/2057400965372805429 · Twitter Post