CVE-2026-45498

highpriority · act · 90OT risk · criticalKEV · exploitedEPSS 0.013 · 70 %ileexploit · PoCDEEURUUS

grimoire priorityP0 · Act now

Exploitable?

Yes · in the wild

CISA KEV · 1 exploit · PoC

Likely / severe?

1.27% (70th) EPSS

CVSS 7.5 · high

Is it mine?

7 products

Check your exposure

Who says so?

6 sources

cnnvd · enisa_euvd · fstec_bdu · cert_bund

added 2026-05-20remediate by 2026-06-03

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.

EPSS · scored 2026-10-22

Microsoft Defender Denial of Service Vulnerability

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

FixedMicrosoft Defender Antimalware Platformmsrc_csaf
4.18.26040.7:Security Update:https://www.microsoft.com/en-us/wdsi/defenderupdates
https://www.microsoft.com/en-us/wdsi/defenderupdates

cvss

Technical severity, 0–10. One row per scoring source.

7.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 4–7.5

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 3.6

v3.14mediumAV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Lsecondary · FSTEC (BDU) RU

v3.14mediumCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:Csecondary · ENISA EU

v3.14mediumCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Lsecondary · secure@microsoft.com USexploitability 2.5 · impact 1.4

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Hsecondary · CVSS-BT (t0sche)

v3.14mediumCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:Csecondary · Microsoft Security Response Center US

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: active · Automatable: no · Technical Impact: partialcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-400USCWE-400USCWE-400US

exploits (1)

Public proof-of-concept and weaponised exploit code.

salihuahmad105-creator/Vulnerability-scannerDESIGN AND IMPLEMENTATION OF A VULNERABILITY SCANNER FOR CVE-2026-45498 IN MICROSOFT DEFENDERPoC · poc_in_github

affected products (7)

Products and version ranges known to be affected.

Microsoft Defender Antimalware Platform <4.18.26040.7all versionscert_bundDE
Microsoft Defender≤ Antimalware Platform <4.18.26040.7cert_bundDE
Microsoft Microsoft Defender Antimalware Platform4.0.0.0 → 4.18.26040.7enisa_euvdEU
Microsoft Corp Microsoft Defender Antimalware Platform4.18.26030.3011 → 4.18.26040.7fstec_bduRU
Microsoft Microsoft Defender Antimalware Platformall versionsfixedmsrc_csafUS
Microsoft Microsoft Defender Antimalware Platform< 4.18.26040.7msrc_csafUS
microsoft defender antimalware platform< 4.18.26040.7nvdUScpe:2.3:a:microsoft:defender_antimalware_platform:*:*:*:*:*:*:*:*

advisories (2)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2026-1603Microsoft Defender und Malware Protection Engine: Mehrere SchwachstellenDeutsch2026-05-19csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Microsoft Defender und Microsoft Malware Protection Engine ausnutzen, um seine Privilegien zu erhöhen, um beliebigen Code auszuführen und um einen Denial of Service Zustand herbeizuführen.
msrc_CVE-2026-45498Microsoft Defender Denial of Service Vulnerability2026-05-19csaf · msrc_csafUS
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu cert_bund msrc_csaf nvd NVD CVE.org MITRE

published 2026-05-20modified 2026-07-23

references (5)

External citations — patches, advisories, analysis.

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45498 cnnvd
https://nvd.nist.gov/vuln/detail/CVE-2026-45498 cnnvd
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45498 enisa_euvd
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45498Vendor Advisorynvd
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-45498Third Party AdvisoryUS Government Resourcenvd

scry

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