high Known exploitedREV. 01
CVE-2026-45498Microsoft Defender — unauthenticated denial of service
Microsoft reports a flaw in Defender that lets an attacker exhaust a resource and take the service down over the network, with no sign-in needed. Neither the vendor entry nor the catalog says which component is at fault or what triggers it.
Read the risk
THE VITAL STATS- CVSS score
- 7.5/ 10 CVSS v3.1
- EPSS probability
- 63% Likelihood of exploitation
- Attack complexity
- Low Conditions needed to exploit
- Known exploited
- Yes — CISA KEV
- CVE published
- 2026-05-20
- Added to KEV
- 2026-05-20
- Exploit published
- Not recorded
- Confidence
- medium
- Kill chain
- impact
- MITRE ATT&CK
- T1499
- Severity
- high
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attacker needsNetwork access to the affected Defender service; no credentials needed.
Behind the card
4 REFERENCES- 01CVE recordNVD recordnvd.nist.gov
- 02CISACISA Known Exploited Vulnerabilities catalogcisa.gov
- 03Vendor advisorymsrc.microsoft.commsrc.microsoft.com
- 04Writeupcisa.govcisa.gov
Field-level provenanceTRACE THE SOURCES +
Which source supports each field, when it was retrieved, and who extracted it.
| Fields | Source | Retrieved | Extractor | Confidence |
|---|---|---|---|---|
| cvss, exploitation.attack_complexity, exploitation.exploit_available, references, published_at | nvd.nist.gov | 2026-09-24 | scrty-crds-pipeline/0.1 | high |
| exploitation.known_exploited, exploitation.kev_added | cisa.gov | 2026-09-24 | scrty-crds-pipeline/0.1 | high |
| epss | api.first.org | 2026-09-24 | scrty-crds-pipeline/0.1 | high |
| title, summary, severity, remediation, mitre_attack, kill_chain, recommended_action, confidence, tags, exploitation.prerequisites | nvd.nist.gov | 2026-09-24 | claude-code | high |
Printing history
THE RECORD- r1Initial base card
First printing. This card has not been reprinted since publication.