CVSS4
Severitymedium
WeaknessCWE-400
EPSS1.3%69.4th percentile
Exploited3 KEV sources
Ransomware useUnknown
Federal fix dueJun 3, 2026
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
patch window
Called exploited 1 days before disclosure.
Measured from the CVE publication date to the earliest of 3 KEV catalogues that list it.
The life of this vulnerability
- CVE published
- First KEV listing1d
- Last KEV listing1d
- Last sightingsame day
Gaps are compressed to equal steps. The elapsed time is printed under each.
Which catalogues call it exploited
- CISA KEVUS federallisted May 20, 2026
- EUVDENISA, European Unionlisted May 20, 2026
- VulnCheck KEVcommercial researchlisted May 19, 2026
- CIRCLaggregator, mirrors the abovelisted May 20, 2026, not counted
Sources3 of 3
Listings differ by1 d
Strongest claimconfirmed
3 catalogues list it. CIRCL aggregates the others and is shown but not counted.
Public exploitation evidence
- reported exploitationwww.cisa.gov/sites/default/files/feeds/known_exploited_vulne
- reported exploitationapi.msrc.microsoft.com/cvrf/v3.0/cvrf/2026-May
- reported exploitationmsrc.microsoft.com/update-guide/vulnerability/CVE-2026-45498
3 public reports collected from VulnCheck and CIRCL, first on May 19, 2026. Each links to its original source. We have not verified them.
Description
Microsoft Defender Denial of Service Vulnerability
Required action (CISA)
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.