Security readout for executives and security teams
Plain-English summary
A network attacker without credentials or user interaction can trigger a flaw in Windows LSASS, disrupting authentication-related services and system availability. The issue affects numerous Windows client and server releases, including legacy servers. It does not provide confidentiality or integrity impact according to the supplied CVSS assessment.
Executive priority
Treat this as a high-priority availability issue, especially on authentication infrastructure and legacy servers. Establish affected asset counts, reduce network reachability, and deploy Microsoft’s applicable update through an expedited but controlled process. There is no supplied evidence of active exploitation.
Technical view
CVE-2026-20875 is a remotely reachable null-pointer dereference in Windows LSASS, classified as CWE-476. Its CVSS 3.1 score is 7.5: network-accessible, low complexity, unauthenticated, and requiring no user interaction. The documented impact is denial of service with high availability loss.
Likely exposure
Exposure exists where listed Windows 10, Windows 11, or Windows Server releases are running without the applicable Microsoft security update and an attacker can reach the affected network service. The bundle does not identify ports, protocols, configurations, or exact fixed build numbers.
Exploitation context
The supplied record does not establish active exploitation, and the CVE is not listed as KEV in the bundle. CVSS marks exploit maturity as unproven. Nevertheless, unauthenticated network reachability and low stated attack complexity make unpatched, reachable systems a meaningful availability risk.
Researcher notes
The source bundle identifies remote unauthenticated denial of service through a null-pointer dereference but provides no protocol, attack surface, proof of concept, or fixed-build details. Windows 11 23H2 appears twice with equivalent base version data. Validate product applicability and remediation directly against the Microsoft advisory.
Mitigation direction
- Review Microsoft’s advisory and install the applicable security update for each affected Windows release.
- Prioritize reachable servers providing authentication or other business-critical services.
- Restrict unnecessary network access to affected systems using existing segmentation and access controls.
- Confirm extended-support update eligibility for legacy Windows Server releases.
- Follow current Microsoft guidance if an applicable update is unavailable.
Validation and detection
- Inventory systems running the listed Windows client and server releases.
- Compare installed update and build information with Microsoft’s CVE advisory.
- Verify affected network services are accessible only from required security zones.
- Review monitoring records for unexplained LSASS failures or related availability incidents.
- Recheck Microsoft guidance for revised affected-version or remediation information.
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-476: 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-2026-20875 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
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/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.
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:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C3.93.6microsoftVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/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.
- 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
- Windows Local Security Authority Subsystem Service (LSASS) Denial of Service VulnerabilityCVE reference, microsoft · vendor-advisory, patch
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.
NULL Pointer Dereference
NULL Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.