Threats / Microsoft / CVE-2026-41091
CVE-2026-41091
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Microsoft Defender vulnerability
Microsoft Defender contains a link following vulnerability (CWE-59) allowing authorized attackers to elevate privileges locally.
Verdict
Today item — known-exploited.
An authenticated local attacker can exploit improper link resolution in Microsoft Defender to gain elevated system privileges. The vulnerability has been observed in active exploitation.
CISA KEV Yes · 2026-05-205EPSS 0.09641 (verify live)6CVSS 7.83CISA SSVC Exploitation: active · Automatable: no · Impact: total4
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
4 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-05-20).
Probability (EPSS)
EPSS 0.09641 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 7.8 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C) · Affected: Microsoft, Defender. Confirm exact fixed builds in the vendor advisory.CVSS — CNA-assigned (CVE.org), version 3.1, set at disclosure.
Weakness (CWE)
Mapped to CWE-59 Link Following — weakness family: Path traversal / file.CWE — CNA-assigned (CVE.org); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: no · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog the same day the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a symbolic or hard link in a location where Defender processes files with elevated privileges.
Business
An insider or compromised local account gains system-level access, bypassing security boundaries.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I direct Defender's file operations to follow my malicious link to a sensitive system location.
Business
Defender's elevated context is abused to modify protected files or registry entries.
3
Lateral reach — past segmentation narrative 3
Attacker
I achieve code execution or configuration changes running under SYSTEM or Administrator privileges.
Business
Endpoint security controls are compromised, enabling lateral movement, persistence, or data exfiltration.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05