Security readout for executives and security teams
Plain-English summary
A Microsoft Word type-confusion flaw could let an unauthorized attacker run code on an affected system. Successful exploitation could compromise sensitive data, alter files, or disrupt operations. The supplied CVSS score is 8.4, making prompt assessment and vendor-directed patching appropriate.
Executive priority
Treat this as a high-priority patching and exposure-validation task. Potential impact spans data theft, unauthorized changes, and service disruption, although active exploitation is not established. Request rapid inventory results, update coverage, and documented exceptions for affected Office, Word, and SharePoint assets.
Technical view
CVE-2026-40367 is a CWE-822 incompatible-type resource access vulnerability affecting listed Microsoft Office, Word, Microsoft 365, and SharePoint products. The supplied vector is local, low complexity, requires no privileges or user interaction, and indicates high confidentiality, integrity, and availability impact. The bundle does not describe the triggering path.
Likely exposure
Exposure is limited to the listed Microsoft 365 Apps for Enterprise, Office 2019, Office LTSC 2021/2024, Office LTSC for Mac 2021/2024, Word 2016, and SharePoint 2016/2019/Subscription Edition versions. The bundle provides broad version identifiers but no patched build numbers, so asset-level comparison requires Microsoft guidance.
Exploitation context
The CVSS vector indicates local attack access with low complexity, no privileges, and no user interaction. However, the source bundle provides no exploit narrative, proof of concept, indicators, or evidence of active exploitation. The CVE is not listed as KEV in the supplied data.
Researcher notes
The description identifies type confusion and maps the issue to CWE-822. CVSS 3.1 is 8.4 with AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. The sources do not disclose the vulnerable component, malformed object, execution context, attack chain, indicators, or fixed builds. Avoid inferring document-delivery or server-side exploitation paths.
Mitigation direction
- Review the Microsoft advisory for product-specific security updates and patched build numbers.
- Apply applicable Microsoft updates using established change and rollback procedures.
- Prioritize systems handling untrusted documents or sensitive business data.
- Restrict unnecessary access to affected applications until updates are verified.
Validation and detection
- Inventory installations of every product and version named in the affected list.
- Compare installed build numbers with Microsoft advisory guidance; the bundle lacks patched build details.
- Confirm applicable security updates installed successfully across managed endpoints and servers.
- Document exceptions and reassess them when Microsoft publishes additional guidance.
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-822: 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-40367 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
- 8.4 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:N/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:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C2.55.9microsoftVulnerability scoring details
Base CVSS 3.1 score
8.4HighVector: CVSS:3.1/AV:L/AC:L/PR:N/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
- Microsoft Word Remote Code Execution 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.
Untrusted Pointer Dereference
Untrusted Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.