CVE-2026-45498 (GCVE-0-2026-45498)

Vulnerability from cvelistv5 – Published: 2026-05-20 13:09 – Updated: 2026-08-10 15:13
VLAI CISA Previdian
Title
Microsoft Defender Denial of Service Vulnerability
Summary
Microsoft Defender Denial of Service Vulnerability
Severity
4 (Medium)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C
SSVC
Exploitation: active Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-05-21 03:55 UTC
CWE
  • CWE-400 - Uncontrolled Resource Consumption
Assigner
References
Impacted products
Vendor Product Version CPE status
Microsoft Microsoft Defender Antimalware Platform Affected: 4.0.0.0 , < 4.18.26040.7 (custom)
    cpe:2.3:a:microsoft:microsoft_defender:*:*:*:*:*:*:*:*
Create a notification for this product.
Date Public
2026-05-19 14:00
CISA
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: e18ff94c-33da-466f-9a04-6a9d76c6097d

Vulnerability ID: CVE-2026-45498

Status: Confirmed

Status Updated: 2026-05-20 00:00 UTC

Exploited: Yes

Timestamps
First Seen: 2026-05-20
Asserted: 2026-05-20
Scope
Notes: KEV entry: Microsoft Defender Denial of Service Vulnerability | Affected: Microsoft / Defender | Description: Microsoft Defender contains an unspecified vulnerability that allows for denial of service. | Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. | Due date: 2026-06-03 | Known ransomware campaign use (KEV): Unknown | Notes (KEV): https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-45498 ; https://nvd.nist.gov/vuln/detail/CVE-2026-45498
Evidence

Type: Vendor Report

Signal: Successful Exploitation

Confidence: 80%

Source: cisa-kev

Details
Cwes
Feed CISA Known Exploited Vulnerabilities Catalog
Product Defender
Due Date 2026-06-03
Date Added 2026-05-20
Vendorproject Microsoft
Vulnerabilityname Microsoft Defender Denial of Service Vulnerability
Knownransomwarecampaignuse Unknown
References
Created: 2026-05-20 18:00 UTC | Updated: 2026-05-20 18:00 UTC
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: c46c47c1-3450-4ced-8bec-e2c77b5d96c9

Vulnerability ID: CVE-2026-45498

Status: Confirmed

Status Updated: 2026-06-01 13:29 UTC

Exploited: Yes

Timestamps
First Seen: 2026-06-01
Asserted: 2026-06-01
Scope
Notes: KEVIntel entry: Microsoft Defender Denial of Service Vulnerability | Affected: Microsoft / Microsoft Defender Antimalware Platform | CVSS: 4.0 (MEDIUM) | EPSS: 0.025 | Used in malware: unknown | Not yet in CISA KEV: False
Evidence

Type: Public Report

Signal: Successful Exploitation

Confidence: 70%

Source: kevintel

Details
Feed KEVIntel (kevintel.com)
Title Microsoft Defender Denial of Service Vulnerability
Vendor Microsoft
Product Microsoft Defender Antimalware Platform
Added Date 2026-06-01T13:29:26.865Z
Cvss Score 4.0
Epss Score 0.025
Cvss Severity MEDIUM
Epss Percentile 0.8263
Used In Malware unknown
Ahead Of Cisa Kev 
{
  "count": 1,
  "unit": "day"
}
Not Yet In Cisa Kev False
References
Created: 2026-06-23 14:03 UTC | Updated: 2026-07-10 06:14 UTC
Show details on NVD website
To clipboard 

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Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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