Threats / Microsoft / CVE-2026-45498
CVE-2026-45498
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Microsoft Defender vulnerability
Microsoft Defender contains an unspecified vulnerability enabling denial of service attacks. The vulnerability has been observed exploited in the wild.
Verdict
Today item — known-exploited.
An unspecified denial of service vulnerability in Microsoft Defender poses operational risk to systems relying on this security product. Active exploitation in the wild indicates practical threat, though low EPSS score suggests limited prevalence.
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
3 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 0.025 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Microsoft, Defender. Confirm exact fixed builds in the vendor advisory.
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 input or trigger conditions that cause Microsoft Defender to consume excessive resources or crash.
Business
Security monitoring and threat detection capabilities are degraded or unavailable, leaving systems exposed during the outage.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I exploit the vulnerability to disable or destabilize Defender across multiple endpoints in a target environment.
Business
Organizational security posture weakens significantly, increasing window of opportunity for secondary attacks 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