CVE-2026-45498
Microsoft Defender Denial of Service Vulnerability - [Actively Exploited]
Description
Microsoft Defender Denial of Service Vulnerability
INFO
Published Date :
May 20, 2026, 1:16 p.m.
Last Modified :
May 28, 2026, 10:49 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CISA KEV (Known Exploited Vulnerabilities)
For the benefit of the cybersecurity community and network defenders—and to help every organization better manage vulnerabilities and keep pace with threat activity—CISA maintains the authoritative source of vulnerabilities that have been exploited in the wild.
Microsoft Defender contains an unspecified vulnerability that allows for denial of service.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Unknown
https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-45498 ; https://nvd.nist.gov/vuln/detail/CVE-2026-45498
Affected Products
The following products are affected by CVE-2026-45498
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | f38d906d-7342-40ea-92c1-6c4a2c6478c8 | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | HIGH | [email protected] |
Public PoC/Exploit Available at Github
CVE-2026-45498 has a 4 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-45498.
| URL | Resource |
|---|---|
| https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45498 | Vendor Advisory |
| https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-45498 | Third Party Advisory US Government Resource |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-45498 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-45498
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
CVE-2026-41091 / CVE-2026-45498 Microsoft Defender vulnerability scanner
Python
Actively exploited CVE scanners from CISA KEV + Twitter trends - Drupal SQLi, PAN-OS RCE, Android ADBD, GHE RCE, BeyondTrust, Defender, and more
Python
None
ai-agent cve cybersecurity epss kev llm mitre-attack nvd soc threat-intelligence vulnerability vulnerability-scanner
Python Batchfile HTML Dockerfile Shell
SecDB - Security Feeds
cve security-feeds vulnerability
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-45498 vulnerability anywhere in the article.
-
TheCyberThrone
Microsoft Patch Tuesday — June 2026
Microsoft’s June 2026 Patch Tuesday is the largest release since the Patch Tuesday program began, surpassing the previous record of 167 CVEs set in October 2025. This month’s release addresses 206 vul ... Read more
-
The Hacker News
Microsoft Defender RoguePlanet Zero-Day Grants SYSTEM Access on Updated Windows
The anonymous security researcher going by the name Chaotic Eclipse (aka Nightmare-Eclipse) has released a proof-of-concept (PoC) exploit for yet another Microsoft Defender zero-day named RoguePlanet. ... Read more
-
CybersecurityNews
Microsoft MSRC Allegedly Dismissed Dependency Confusion Vulnerability, Claims Researcher
A dependency confusion vulnerability affecting Microsoft’s Azure Portal after the Microsoft Security Response Center (MSRC) closed the case, claiming the confirmed remote code execution evidence did n ... Read more
-
CybersecurityNews
Microsoft Clarifies It Won’t Sue Security Researchers Amid Nightmare-Eclipse Controversy
Microsoft has clarified its stance, reducing perceived legal threats and reaffirming its commitment to coordinated vulnerability disclosure, following significant backlash from the security research c ... Read more
-
The Hacker News
Microsoft Slams Public Zero-Day Disclosures Amid GitHub Researcher Account Removal
Microsoft has come out strongly in favor of Coordinated Vulnerability Disclosure (CVD), urging the research community to share their findings and give affected vendors an opportunity to better underst ... Read more
-
CybersecurityNews
Microsoft Warns Public Release of Zero-Day Details Before Vendor Coordination
Microsoft has issued a strong warning after multiple zero-day vulnerabilities were publicly disclosed without prior coordination, raising concerns about increased risk to users and enterprise environm ... Read more
-
The Cyber Express
Critical Ghost CMS Vulnerability Exploited to Hack 700+ Websites
A critical Ghost CMS vulnerability identified as CVE-2026-26980 has been exploited in a widespread cyber campaign that compromised more than 700 websites, including platforms associated with major ins ... Read more
-
CybersecurityNews
CISA Warns of Microsoft Defender 0-Day Vulnerabilities Exploited in Attacks
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added two critical Microsoft Defender vulnerabilities to its Known Exploited Vulnerabilities (KEV) catalog, warning organizations o ... Read more
-
SentinelOne
The Good, the Bad and the Ugly in Cybersecurity – Week 21
The Good | Joint Operations Dismantle Cybercrime Infrastructure, Infostealers & Malicious VPNs Over 200 individuals and another 382 suspects have been rounded up in Interpol’s Operation Ramz, an initi ... Read more
-
SentinelOne
The Good, the Bad and the Ugly in Cybersecurity – Week 21
The Good | Joint Operations Dismantle Cybercrime Infrastructure, Infostealers & Malicious VPNs Over 200 individuals and another 382 suspects have been rounded up in Interpol’s Operation Ramz, an initi ... Read more
-
The Cyber Express
Microsoft Patches Actively Exploited Defender Vulnerabilities Affecting Enterprise Systems
Microsoft has confirmed active exploitation of two security vulnerabilities in its security ecosystem, identified as CVE-2026-41091 and CVE-2026-45498, both evaluated under the CVSS scoring system. Th ... Read more
-
TheCyberThrone
CISA adds Seven Vulnerabilities to KEV Catalog
May 21, 2026CISA has added seven vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog based on confirmed evidence of active exploitation. The batch spans Microsoft Windows, Microsoft I ... Read more
-
The Hacker News
Microsoft Warns of Two Actively Exploited Defender Vulnerabilities
Microsoft has disclosed that a privilege escalation and a denial-of-service flaw in Defender has come under active exploitation in the wild. The former, tracked as CVE-2026-41091, is rated 7.8 on the ... Read more
-
CybersecurityNews
New Microsoft Defender 0‑Days Actively Exploited in the Wild
Two newly disclosed Microsoft Defender vulnerabilities are being actively exploited in the wild, enabling local attackers to elevate privileges to SYSTEM and potentially disrupt endpoint protection ac ... Read more
-
security.nl
Beveiligingslekken in Microsoft Defender actief misbruikt bij aanvallen
Aanvallers maken actief misbruik van twee kwetsbaarheden in Microsoft Defender, de antivirussoftware van Microsoft die onder andere in Windows is ingebouwd. Het techbedrijf heeft updates uitgerold om ... Read more
The following table lists the changes that have been made to the
CVE-2026-45498 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Modified Analysis by [email protected]
May. 28, 2026
Action Type Old Value New Value -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
May. 27, 2026
Action Type Old Value New Value Removed CWE CWE-400 -
Modified Analysis by [email protected]
May. 26, 2026
Action Type Old Value New Value Removed CWE NVD-CWE-noinfo Changed CPE Configuration OR *cpe:2.3:a:microsoft:defender_antimalware_platform:*:*:*:*:*:*:*:* versions from (including) 4.18.26030.3011 up to (excluding) 4.18.26040.7 OR *cpe:2.3:a:microsoft:defender_antimalware_platform:*:*:*:*:*:*:*:* versions up to (excluding) 4.18.26040.7 -
CVE Modified by [email protected]
May. 26, 2026
Action Type Old Value New Value Added CWE CWE-400 -
Initial Analysis by [email protected]
May. 20, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE NVD-CWE-noinfo Added CPE Configuration OR *cpe:2.3:a:microsoft:defender_antimalware_platform:*:*:*:*:*:*:*:* versions from (including) 4.18.26030.3011 up to (excluding) 4.18.26040.7 Added Reference Type Microsoft Corporation: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45498 Types: Vendor Advisory Added Reference Type CISA-ADP: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-45498 Types: Third Party Advisory, US Government Resource -
CVE CISA KEV Update by 9119a7d8-5eab-497f-8521-727c672e3725
May. 20, 2026
Action Type Old Value New Value Added Date Added 2026-05-20 Added Due Date 2026-05-20 Added Required Action 2026-05-20 Added Vulnerability Name 2026-05-20 -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
May. 20, 2026
Action Type Old Value New Value Added CWE CWE-400 Added Reference https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-45498 -
New CVE Received by [email protected]
May. 20, 2026
Action Type Old Value New Value Added Description Microsoft Defender Denial of Service Vulnerability Added CVSS V3.1 AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Added Reference https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45498