Security readout for executives and security teams
Plain-English summary
This Windows Kernel flaw could let a user who already has limited local access gain powerful system privileges. Successful exploitation could expose data, alter systems, or disrupt services. It affects multiple Windows Server releases from 2012 through 2025, including specified Server Core installations.
Executive priority
Treat this as a high-priority patching issue, especially on shared, administrative, or business-critical servers. It is not described as remotely exploitable without prior access, but it could turn an initial low-privilege foothold into full system compromise. Track remediation to completion rather than relying solely on perimeter controls.
Technical view
CVE-2026-35420 is a heap-based buffer overflow, classified as CWE-122, in the Windows Kernel. The CVSS 3.1 score is 7.8. Exploitation requires local access and low privileges, but no user interaction; successful exploitation may compromise confidentiality, integrity, and availability.
Likely exposure
Exposure applies to the listed Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2022 23H2, and 2025 products and specified Server Core installations. Systems allowing local, remote-interactive, or application-mediated access by lower-privileged users warrant particular attention. The supplied data does not define broader version ranges.
Exploitation context
The CVSS vector indicates local attack access, low complexity, low privileges, and no user interaction. The bundle marks this CVE as absent from KEV and provides no cited evidence of active exploitation. That does not establish that exploitation is impossible or will not emerge.
Researcher notes
The public bundle identifies the weakness class, CVSS vector, affected products, and vendor advisory, but not the vulnerable kernel component, exploitation primitive, indicators, or specific update identifiers. Researchers and vulnerability managers should use the Microsoft advisory to confirm applicable updates and affected-build details without assuming exploitability beyond the documented local privilege-escalation conditions.
Mitigation direction
- Review Microsoft’s advisory and deploy the applicable security update for each affected Windows Server release.
- Prioritize servers where lower-privileged users can sign in or run workloads.
- Restrict unnecessary local and remote-interactive access until remediation is complete.
- Follow Microsoft guidance for deployment prerequisites, restart requirements, and superseding updates.
Validation and detection
- Inventory Windows Server editions and versions against the supplied affected-product list.
- Compare installed security updates with the applicable Microsoft advisory entry.
- Confirm successful update installation and any required restart on each affected server.
- Re-scan remediated systems and investigate failed, pending, or rolled-back updates.
- Review endpoint telemetry for unexpected privilege elevation or kernel instability.
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-122: 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 lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-35420 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
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C1.85.9microsoftVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 Kernel Elevation of Privilege 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.
Heap-based Buffer Overflow
Heap-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.