Security readout for executives and security teams
Plain-English summary
CVE-2026-45498 is a Microsoft Defender Antimalware Platform denial-of-service issue. Public data rates it medium severity, but CISA lists it as known exploited. The likely business impact is disruption of Defender availability on affected systems, not data theft or code execution based on current sources.
Executive priority
Treat this as prompt patching work, not a crisis response unless Defender outages are observed. KEV listing means exploitation is credible, and Defender availability is a security control dependency. Prioritize broad endpoint update compliance and exception tracking.
Technical view
The CVSS 3.1 vector is 4.0: local attack, low complexity, no privileges, no user interaction, unchanged scope, and low availability impact. The listed weakness is CWE-400, uncontrolled resource consumption. The affected product listed is Microsoft Defender Antimalware Platform version 4.0.0.0.
Likely exposure
Exposure is most relevant on Windows assets running Microsoft Defender Antimalware Platform 4.0.0.0. The attack vector is local, so risk depends on an attacker or malware already executing on the host. CISA KEV status raises urgency despite limited technical impact.
Exploitation context
CISA KEV indicates known exploitation. The provided public sources do not describe exploit mechanics, targeting, scale, or observed campaigns. The vulnerability is denial of service only in the available CVSS data, with no confidentiality or integrity impact listed.
Researcher notes
Evidence is thin in the provided sources. MSRC and CVE data identify a Defender Antimalware Platform DoS with CWE-400 and an available fix, but do not provide root-cause detail. Avoid assuming remote exploitation or code execution from the current record.
Mitigation direction
- Review Microsoft’s MSRC advisory for CVE-2026-45498 and apply the listed Defender platform update.
- Prioritize remediation on internet-facing, high-value, and user workstation fleets.
- Use normal enterprise update channels to keep Microsoft Defender components current.
- Monitor CISA KEV guidance for required remediation timelines.
Validation and detection
- Inventory endpoints for Microsoft Defender Antimalware Platform version 4.0.0.0.
- Confirm the installed platform version is no longer listed as affected by Microsoft.
- Verify update compliance through endpoint management or Defender administration tooling.
- Check security monitoring for Defender service instability on unpatched hosts.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-400: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-45498 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 4 (3.1)
- Known Exploited
- Yes
- Published
Vector: 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
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CISA KEV status
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C2.51.4microsoftVulnerability scoring details
Base CVSS 3.1 score
4MediumVector: 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
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- Added to KEVCISA-ADP
CISA Known Exploited Vulnerabilities metadata lists this CVE as known exploited.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- Microsoft Defender Denial of Service VulnerabilityCVE reference, microsoft · vendor-advisory, patch
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-45498CVE reference, CISA-ADP · government-resource
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Uncontrolled Resource Consumption
Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.